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New strategies cut esophageal damage from AFib catheter ablation
NATIONAL HARBOR, MD. – Thermal injury of a patient’s esophagus during radiofrequency catheter ablation of atrial fibrillation is notorious as a relatively common and problematic complication of the procedure, but two new approaches showed promise for substantially cutting the risk of esophageal thermal injury and the potential for the most severe damage: perforation.
One of these innovations is intensive esophageal cooling with a commercially marketed, fluid-chilled catheter placed in a patient’s esophagus during radiofrequency catheter ablation that keeps the inner surface of the esophagus at 4°C. This approach cut the incidence of periprocedural episodes of endoscopically detected esophageal thermal injury from 20% among controls to 3% in patients who had esophageal cooling in a randomized study with 120 patients, Mark M. Gallagher, MD, said at the annual International AF Symposium. The same device can also maintain a temperature on the inner surface of the esophagus of 42 ° C in patients undergoing cryoablation of atrial fibrillation, noted Dr. Gallagher, a cardiac electrophysiologist at St. George’s University Hospitals in London.
A second approach to cutting esophageal damage focuses on modifying the energy delivery with a radiofrequency ablation method known as high-power short-duration (HPSD). As the name says, this strategy uses a relatively high level of radiofrequency energy, 50 watts in the reported experience, for the brief interval of about 7 seconds, ideally delivering an overall Ablation Index of at least 350 but below 360, said Thomas Deneke, MD, an electrophysiologist, professor, and cochief of cardiology at the Heart Center in Bad Neustadt, Germany.
Dr. Deneke and his associates in Bad Neustadt began using this HPSD approach in mid-2019, and by early 2020 they had data from 179 patients who underwent first-time catheter ablation of atrial fibrillation (AFib), all of whom had undergone routine esophageal endoscopy 1-3 days after their treatment. Eight patients (4%) showed evidence of endoscopically detected esophageal lesions (EDEL), including three patients (2%) with an actual esophageal ulcer, and one (0.6%) who developed a perforation that healed after 52 days, Dr. Deneke reported. An additional 55 patients underwent a redo catheter ablation procedure using the HPSD method during this period, and in that group follow-up endoscopy in all patients showed EDEL in two patients (4%). In contrast, during Jan. 2012–May 2019, the same German center treated 2,102 patients who had a first radiofrequency catheter ablation using convention energy levels and treatment times, which resulted in 291 patients having an EDEL (14%), including 94 (4%) with an ulcer, and six patients (0.3%) with an esophageal perforation, he said.
His center’s recent safety experience with HPSD radiofrequncy ablation, compared with the historical controls, suggests that this technique can produce a substantial reduction in esophageal thermal injury, but HPSD has not completely eliminated the risk and hence there is need for continued alertness for this potential complication Dr. Deneke concluded. The HPSD method is also limited by having “a very narrow window” between efficacy at an Ablation Index of 350 and safety when the index remains below 360, he added.
The randomized study that Dr. Gallagher ran at St. George’s followed an analysis he and his associates recently published that suggested efficacy using esophageal cooling in prior reports when the data combined in a meta-analysis (J Interv Card Electrophysiol. 2019 Nov 22. doi: 10.1007/s10840-019-00661-5). They also concluded that the clinical setting required a temperature control device with an enhanced capacity for rapid cooling, which prior studies had lacked. So they turned to a Food and Drug Administration–approved catheter designed for placement in the esophagus for the purpose of either whole-body cooling or warming.
The study randomized a total of 187 patients, but collected follow-up endoscopy at 5-7 days after the ablation procedure on 120 patients, of whom 60 received esophageal cooling and 60 did not. The types of ablations performed on patients in the two study arms were similar, and use of esophageal cooling had no impact on treatment duration or efficacy, either acute and longer term, Dr. Gallagher reported.
Cooling had a marked and statistically significant impact on endoscopically detected thermal injury. Although two patients in the group that underwent cooling had injuries, in one of these cases the injury involved a protocol violation: Radiofrequency ablation mistakenly occurred after the cooling device shut off, and it was during this period when the injury happened. In the second case of thermal injury, blinded scoring judged the injury as grade 2 in severity – an erosion of less than 5 mm – on a nine-item scale that ranged from zero to grade 6, the most severe level denoting a fistula. By contrast, among the 12 patients with thermal injury in the nonprotected subgroup, one patient had a grade 5a lesion denoting a deep ulcer, one had a 4b denoting a superficial ulcer with a clot, and four had a 4a lesion defined as a clean superficial ulcer.
“This is really effective. It’s the first study to show reduced damage without affecting ablation efficacy,” Dr. Gallagher said. He plans to now use this method of esophageal protection routinely for his AFib ablation patients who pay privately, and for patients insured under the national U.K. system once this coverage is approved. Dr. Deneke expressed his interest in also using this approach to esophageal protection, but noted that currently he did not have access to the cooling catheter that Dr. Gallagher used because of regulatory constraints.
The esophageal cooling study was sponsored by Attune Medical, which markets the cooling device. Dr. Gallagher has received research funding from Attune Medical, and has received honoraria as a speaker on behalf of Biosense Webster and Medtronic. Dr. Deneke has been a speaker on behalf of Abbott, Biosense Webster, Biotronik, and Boston Scientific, and his institution has received research funding from Biosense Webster and Securus/Boston Scientific.
NATIONAL HARBOR, MD. – Thermal injury of a patient’s esophagus during radiofrequency catheter ablation of atrial fibrillation is notorious as a relatively common and problematic complication of the procedure, but two new approaches showed promise for substantially cutting the risk of esophageal thermal injury and the potential for the most severe damage: perforation.
One of these innovations is intensive esophageal cooling with a commercially marketed, fluid-chilled catheter placed in a patient’s esophagus during radiofrequency catheter ablation that keeps the inner surface of the esophagus at 4°C. This approach cut the incidence of periprocedural episodes of endoscopically detected esophageal thermal injury from 20% among controls to 3% in patients who had esophageal cooling in a randomized study with 120 patients, Mark M. Gallagher, MD, said at the annual International AF Symposium. The same device can also maintain a temperature on the inner surface of the esophagus of 42 ° C in patients undergoing cryoablation of atrial fibrillation, noted Dr. Gallagher, a cardiac electrophysiologist at St. George’s University Hospitals in London.
A second approach to cutting esophageal damage focuses on modifying the energy delivery with a radiofrequency ablation method known as high-power short-duration (HPSD). As the name says, this strategy uses a relatively high level of radiofrequency energy, 50 watts in the reported experience, for the brief interval of about 7 seconds, ideally delivering an overall Ablation Index of at least 350 but below 360, said Thomas Deneke, MD, an electrophysiologist, professor, and cochief of cardiology at the Heart Center in Bad Neustadt, Germany.
Dr. Deneke and his associates in Bad Neustadt began using this HPSD approach in mid-2019, and by early 2020 they had data from 179 patients who underwent first-time catheter ablation of atrial fibrillation (AFib), all of whom had undergone routine esophageal endoscopy 1-3 days after their treatment. Eight patients (4%) showed evidence of endoscopically detected esophageal lesions (EDEL), including three patients (2%) with an actual esophageal ulcer, and one (0.6%) who developed a perforation that healed after 52 days, Dr. Deneke reported. An additional 55 patients underwent a redo catheter ablation procedure using the HPSD method during this period, and in that group follow-up endoscopy in all patients showed EDEL in two patients (4%). In contrast, during Jan. 2012–May 2019, the same German center treated 2,102 patients who had a first radiofrequency catheter ablation using convention energy levels and treatment times, which resulted in 291 patients having an EDEL (14%), including 94 (4%) with an ulcer, and six patients (0.3%) with an esophageal perforation, he said.
His center’s recent safety experience with HPSD radiofrequncy ablation, compared with the historical controls, suggests that this technique can produce a substantial reduction in esophageal thermal injury, but HPSD has not completely eliminated the risk and hence there is need for continued alertness for this potential complication Dr. Deneke concluded. The HPSD method is also limited by having “a very narrow window” between efficacy at an Ablation Index of 350 and safety when the index remains below 360, he added.
The randomized study that Dr. Gallagher ran at St. George’s followed an analysis he and his associates recently published that suggested efficacy using esophageal cooling in prior reports when the data combined in a meta-analysis (J Interv Card Electrophysiol. 2019 Nov 22. doi: 10.1007/s10840-019-00661-5). They also concluded that the clinical setting required a temperature control device with an enhanced capacity for rapid cooling, which prior studies had lacked. So they turned to a Food and Drug Administration–approved catheter designed for placement in the esophagus for the purpose of either whole-body cooling or warming.
The study randomized a total of 187 patients, but collected follow-up endoscopy at 5-7 days after the ablation procedure on 120 patients, of whom 60 received esophageal cooling and 60 did not. The types of ablations performed on patients in the two study arms were similar, and use of esophageal cooling had no impact on treatment duration or efficacy, either acute and longer term, Dr. Gallagher reported.
Cooling had a marked and statistically significant impact on endoscopically detected thermal injury. Although two patients in the group that underwent cooling had injuries, in one of these cases the injury involved a protocol violation: Radiofrequency ablation mistakenly occurred after the cooling device shut off, and it was during this period when the injury happened. In the second case of thermal injury, blinded scoring judged the injury as grade 2 in severity – an erosion of less than 5 mm – on a nine-item scale that ranged from zero to grade 6, the most severe level denoting a fistula. By contrast, among the 12 patients with thermal injury in the nonprotected subgroup, one patient had a grade 5a lesion denoting a deep ulcer, one had a 4b denoting a superficial ulcer with a clot, and four had a 4a lesion defined as a clean superficial ulcer.
“This is really effective. It’s the first study to show reduced damage without affecting ablation efficacy,” Dr. Gallagher said. He plans to now use this method of esophageal protection routinely for his AFib ablation patients who pay privately, and for patients insured under the national U.K. system once this coverage is approved. Dr. Deneke expressed his interest in also using this approach to esophageal protection, but noted that currently he did not have access to the cooling catheter that Dr. Gallagher used because of regulatory constraints.
The esophageal cooling study was sponsored by Attune Medical, which markets the cooling device. Dr. Gallagher has received research funding from Attune Medical, and has received honoraria as a speaker on behalf of Biosense Webster and Medtronic. Dr. Deneke has been a speaker on behalf of Abbott, Biosense Webster, Biotronik, and Boston Scientific, and his institution has received research funding from Biosense Webster and Securus/Boston Scientific.
NATIONAL HARBOR, MD. – Thermal injury of a patient’s esophagus during radiofrequency catheter ablation of atrial fibrillation is notorious as a relatively common and problematic complication of the procedure, but two new approaches showed promise for substantially cutting the risk of esophageal thermal injury and the potential for the most severe damage: perforation.
One of these innovations is intensive esophageal cooling with a commercially marketed, fluid-chilled catheter placed in a patient’s esophagus during radiofrequency catheter ablation that keeps the inner surface of the esophagus at 4°C. This approach cut the incidence of periprocedural episodes of endoscopically detected esophageal thermal injury from 20% among controls to 3% in patients who had esophageal cooling in a randomized study with 120 patients, Mark M. Gallagher, MD, said at the annual International AF Symposium. The same device can also maintain a temperature on the inner surface of the esophagus of 42 ° C in patients undergoing cryoablation of atrial fibrillation, noted Dr. Gallagher, a cardiac electrophysiologist at St. George’s University Hospitals in London.
A second approach to cutting esophageal damage focuses on modifying the energy delivery with a radiofrequency ablation method known as high-power short-duration (HPSD). As the name says, this strategy uses a relatively high level of radiofrequency energy, 50 watts in the reported experience, for the brief interval of about 7 seconds, ideally delivering an overall Ablation Index of at least 350 but below 360, said Thomas Deneke, MD, an electrophysiologist, professor, and cochief of cardiology at the Heart Center in Bad Neustadt, Germany.
Dr. Deneke and his associates in Bad Neustadt began using this HPSD approach in mid-2019, and by early 2020 they had data from 179 patients who underwent first-time catheter ablation of atrial fibrillation (AFib), all of whom had undergone routine esophageal endoscopy 1-3 days after their treatment. Eight patients (4%) showed evidence of endoscopically detected esophageal lesions (EDEL), including three patients (2%) with an actual esophageal ulcer, and one (0.6%) who developed a perforation that healed after 52 days, Dr. Deneke reported. An additional 55 patients underwent a redo catheter ablation procedure using the HPSD method during this period, and in that group follow-up endoscopy in all patients showed EDEL in two patients (4%). In contrast, during Jan. 2012–May 2019, the same German center treated 2,102 patients who had a first radiofrequency catheter ablation using convention energy levels and treatment times, which resulted in 291 patients having an EDEL (14%), including 94 (4%) with an ulcer, and six patients (0.3%) with an esophageal perforation, he said.
His center’s recent safety experience with HPSD radiofrequncy ablation, compared with the historical controls, suggests that this technique can produce a substantial reduction in esophageal thermal injury, but HPSD has not completely eliminated the risk and hence there is need for continued alertness for this potential complication Dr. Deneke concluded. The HPSD method is also limited by having “a very narrow window” between efficacy at an Ablation Index of 350 and safety when the index remains below 360, he added.
The randomized study that Dr. Gallagher ran at St. George’s followed an analysis he and his associates recently published that suggested efficacy using esophageal cooling in prior reports when the data combined in a meta-analysis (J Interv Card Electrophysiol. 2019 Nov 22. doi: 10.1007/s10840-019-00661-5). They also concluded that the clinical setting required a temperature control device with an enhanced capacity for rapid cooling, which prior studies had lacked. So they turned to a Food and Drug Administration–approved catheter designed for placement in the esophagus for the purpose of either whole-body cooling or warming.
The study randomized a total of 187 patients, but collected follow-up endoscopy at 5-7 days after the ablation procedure on 120 patients, of whom 60 received esophageal cooling and 60 did not. The types of ablations performed on patients in the two study arms were similar, and use of esophageal cooling had no impact on treatment duration or efficacy, either acute and longer term, Dr. Gallagher reported.
Cooling had a marked and statistically significant impact on endoscopically detected thermal injury. Although two patients in the group that underwent cooling had injuries, in one of these cases the injury involved a protocol violation: Radiofrequency ablation mistakenly occurred after the cooling device shut off, and it was during this period when the injury happened. In the second case of thermal injury, blinded scoring judged the injury as grade 2 in severity – an erosion of less than 5 mm – on a nine-item scale that ranged from zero to grade 6, the most severe level denoting a fistula. By contrast, among the 12 patients with thermal injury in the nonprotected subgroup, one patient had a grade 5a lesion denoting a deep ulcer, one had a 4b denoting a superficial ulcer with a clot, and four had a 4a lesion defined as a clean superficial ulcer.
“This is really effective. It’s the first study to show reduced damage without affecting ablation efficacy,” Dr. Gallagher said. He plans to now use this method of esophageal protection routinely for his AFib ablation patients who pay privately, and for patients insured under the national U.K. system once this coverage is approved. Dr. Deneke expressed his interest in also using this approach to esophageal protection, but noted that currently he did not have access to the cooling catheter that Dr. Gallagher used because of regulatory constraints.
The esophageal cooling study was sponsored by Attune Medical, which markets the cooling device. Dr. Gallagher has received research funding from Attune Medical, and has received honoraria as a speaker on behalf of Biosense Webster and Medtronic. Dr. Deneke has been a speaker on behalf of Abbott, Biosense Webster, Biotronik, and Boston Scientific, and his institution has received research funding from Biosense Webster and Securus/Boston Scientific.
THE AF SYMPOSIUM 2020
AI algorithm finds diagnostic AFib signatures in normal ECGs
NATIONAL HARBOR, MD. – Researchers have created an artificial intelligence algorithm that can evaluate a 10-second ECG recording of a person in normal sinus rhythm and tell with a sensitivity and specificity of almost 80% whether or not that person ever had atrial fibrillation episodes some time in the past or will have a first arrhythmia episode in the near future.
Although this algorithm – derived from and then validated with a dataset of nearly 650,000 ECG recordings from more than 180,000 patients – still needs prospective validation, it offers the prospect for a potential revolution in screening for atrial fibrillation (AFib), Paul A. Friedman, MD, cautioned at the annual International AF Symposium. If initial clinical findings are confirmed, it would show that a 10-second, 12-lead ECG recording can provide the same screening scope as what otherwise takes weeks of ambulatory ECG recording with a Holter monitor or an implanted device, explained Dr. Friedman, professor of medicine and chair of the department of cardiovascular medicine at the Mayo Clinic in Rochester, Minn.
This finding “could have important implications for atrial fibrillation screening and for the management of patients with unexplained stroke,” Dr. Friedman and his associates noted in the published report of their study (Lancet. 2019 Sep 7;394[10201]:861-7). “We’re still working to define the window of ECG” recording time that provides the optimal assessment for a history of asymptomatic AFib, but the “possibilities this opens are huge,” Dr. Friedman said in his talk at the symposium. This work sprang from the premise that “subtle signatures” in a brief, apparently normal sinus rhythm ECG tracing can harbor reliable clues about AFib history or an imminent episode.
The 2019 report by Dr. Friedman and associates documented that in the validation phase of their study, the trained artificial intelligence (AI) program identified patients with a history of AFib or an impending arrhythmia event from a single, 10-second ECG that to the naked eye seemed to show normal sinus rhythm with a sensitivity of 79.0%, a specificity of 79.5%, and an accuracy of 79.4%. It also showed an area under a receiver operating characteristic curve of 0.87, meaning that screening for AFib by this method compared favorably with the area-under-the-curve (AUC) results tallied by several widely accepted screening tools, including Pap smears for cervical cancer (AUC of 0.70), mammograms for breast cancer (AUC of 0.85), and CHA2DS2-VASc scoring for estimating stroke risk in AFib patients (AUC of 0.57-0.72), Dr. Friedman said.
The researchers developed the AI algorithm with more than 450,000 10-second ECG tracings collected from roughly 126,000 patients who underwent at least one ECG recording as part of their routine care at the Mayo Clinic during 1993-2017. The goal was for the program to find and validate recurring characteristics in the ECG that consistently linked with a history of or an impending AFib episode and that did not appear in ECG recordings from people without any AFib history. The program this effort produced then underwent further adjustment with the use of more than 64,340 ECGs from an additional 18,116 patients, and then the final product underwent validation testing with a further 130,802 ECGs collected from an additional 36,280 people, the study phase that resulted in the reported sensitivity and specificity estimates.
It’s currently unclear to Dr. Friedman and associates what specific features the program uses to classify patients. It’s an important question, but if the results are reproducible and reliable, this uncertainty shouldn’t slow clinical adoption, he said in an interview.
While “this particular algorithm needs prospective vetting,” a similar algorithm developed by Dr. Friedman and the same research team that uses a 10-second ECG to identify patients with a left ventricular ejection fraction of 35% or less is further advanced in development, and a device that uses this algorithm will soon receive Food and Drug Administration review under a fast track designation that the agency approved in late 2019.
The researchers developed this algorithm for estimating left ventricular function using a strategy similar to their development of a tool for diagnosing AFib (Nat Med. 2019 Jan 7;25[1]:70-4), and results from 100 patients prospectively studied with this approach to ECG analysis and reported at the American Heart Association scientific sessions in November 2019 showed that the algorithm identified substantial left ventricular dysfunction with an AUC of 0.906 (Circulation. 2019 Nov 19;140[suppl 1]:A13447). The same team of investigators has developed an AI algorithm that can calculate a person’s physiologic age based on the ECG recording (Circ Arrhythm Electrophysiol. 2019 Sep;12[9]: 10.1161/CIRCEP.119.007284).
The study received no commercial funding, and Dr. Friedman and coauthors had no relevant disclosures. The Mayo Clinic has licensed a related artificial intelligence algorithm to EKO, and Dr. Friedman may benefit financially from this arrangement.
NATIONAL HARBOR, MD. – Researchers have created an artificial intelligence algorithm that can evaluate a 10-second ECG recording of a person in normal sinus rhythm and tell with a sensitivity and specificity of almost 80% whether or not that person ever had atrial fibrillation episodes some time in the past or will have a first arrhythmia episode in the near future.
Although this algorithm – derived from and then validated with a dataset of nearly 650,000 ECG recordings from more than 180,000 patients – still needs prospective validation, it offers the prospect for a potential revolution in screening for atrial fibrillation (AFib), Paul A. Friedman, MD, cautioned at the annual International AF Symposium. If initial clinical findings are confirmed, it would show that a 10-second, 12-lead ECG recording can provide the same screening scope as what otherwise takes weeks of ambulatory ECG recording with a Holter monitor or an implanted device, explained Dr. Friedman, professor of medicine and chair of the department of cardiovascular medicine at the Mayo Clinic in Rochester, Minn.
This finding “could have important implications for atrial fibrillation screening and for the management of patients with unexplained stroke,” Dr. Friedman and his associates noted in the published report of their study (Lancet. 2019 Sep 7;394[10201]:861-7). “We’re still working to define the window of ECG” recording time that provides the optimal assessment for a history of asymptomatic AFib, but the “possibilities this opens are huge,” Dr. Friedman said in his talk at the symposium. This work sprang from the premise that “subtle signatures” in a brief, apparently normal sinus rhythm ECG tracing can harbor reliable clues about AFib history or an imminent episode.
The 2019 report by Dr. Friedman and associates documented that in the validation phase of their study, the trained artificial intelligence (AI) program identified patients with a history of AFib or an impending arrhythmia event from a single, 10-second ECG that to the naked eye seemed to show normal sinus rhythm with a sensitivity of 79.0%, a specificity of 79.5%, and an accuracy of 79.4%. It also showed an area under a receiver operating characteristic curve of 0.87, meaning that screening for AFib by this method compared favorably with the area-under-the-curve (AUC) results tallied by several widely accepted screening tools, including Pap smears for cervical cancer (AUC of 0.70), mammograms for breast cancer (AUC of 0.85), and CHA2DS2-VASc scoring for estimating stroke risk in AFib patients (AUC of 0.57-0.72), Dr. Friedman said.
The researchers developed the AI algorithm with more than 450,000 10-second ECG tracings collected from roughly 126,000 patients who underwent at least one ECG recording as part of their routine care at the Mayo Clinic during 1993-2017. The goal was for the program to find and validate recurring characteristics in the ECG that consistently linked with a history of or an impending AFib episode and that did not appear in ECG recordings from people without any AFib history. The program this effort produced then underwent further adjustment with the use of more than 64,340 ECGs from an additional 18,116 patients, and then the final product underwent validation testing with a further 130,802 ECGs collected from an additional 36,280 people, the study phase that resulted in the reported sensitivity and specificity estimates.
It’s currently unclear to Dr. Friedman and associates what specific features the program uses to classify patients. It’s an important question, but if the results are reproducible and reliable, this uncertainty shouldn’t slow clinical adoption, he said in an interview.
While “this particular algorithm needs prospective vetting,” a similar algorithm developed by Dr. Friedman and the same research team that uses a 10-second ECG to identify patients with a left ventricular ejection fraction of 35% or less is further advanced in development, and a device that uses this algorithm will soon receive Food and Drug Administration review under a fast track designation that the agency approved in late 2019.
The researchers developed this algorithm for estimating left ventricular function using a strategy similar to their development of a tool for diagnosing AFib (Nat Med. 2019 Jan 7;25[1]:70-4), and results from 100 patients prospectively studied with this approach to ECG analysis and reported at the American Heart Association scientific sessions in November 2019 showed that the algorithm identified substantial left ventricular dysfunction with an AUC of 0.906 (Circulation. 2019 Nov 19;140[suppl 1]:A13447). The same team of investigators has developed an AI algorithm that can calculate a person’s physiologic age based on the ECG recording (Circ Arrhythm Electrophysiol. 2019 Sep;12[9]: 10.1161/CIRCEP.119.007284).
The study received no commercial funding, and Dr. Friedman and coauthors had no relevant disclosures. The Mayo Clinic has licensed a related artificial intelligence algorithm to EKO, and Dr. Friedman may benefit financially from this arrangement.
NATIONAL HARBOR, MD. – Researchers have created an artificial intelligence algorithm that can evaluate a 10-second ECG recording of a person in normal sinus rhythm and tell with a sensitivity and specificity of almost 80% whether or not that person ever had atrial fibrillation episodes some time in the past or will have a first arrhythmia episode in the near future.
Although this algorithm – derived from and then validated with a dataset of nearly 650,000 ECG recordings from more than 180,000 patients – still needs prospective validation, it offers the prospect for a potential revolution in screening for atrial fibrillation (AFib), Paul A. Friedman, MD, cautioned at the annual International AF Symposium. If initial clinical findings are confirmed, it would show that a 10-second, 12-lead ECG recording can provide the same screening scope as what otherwise takes weeks of ambulatory ECG recording with a Holter monitor or an implanted device, explained Dr. Friedman, professor of medicine and chair of the department of cardiovascular medicine at the Mayo Clinic in Rochester, Minn.
This finding “could have important implications for atrial fibrillation screening and for the management of patients with unexplained stroke,” Dr. Friedman and his associates noted in the published report of their study (Lancet. 2019 Sep 7;394[10201]:861-7). “We’re still working to define the window of ECG” recording time that provides the optimal assessment for a history of asymptomatic AFib, but the “possibilities this opens are huge,” Dr. Friedman said in his talk at the symposium. This work sprang from the premise that “subtle signatures” in a brief, apparently normal sinus rhythm ECG tracing can harbor reliable clues about AFib history or an imminent episode.
The 2019 report by Dr. Friedman and associates documented that in the validation phase of their study, the trained artificial intelligence (AI) program identified patients with a history of AFib or an impending arrhythmia event from a single, 10-second ECG that to the naked eye seemed to show normal sinus rhythm with a sensitivity of 79.0%, a specificity of 79.5%, and an accuracy of 79.4%. It also showed an area under a receiver operating characteristic curve of 0.87, meaning that screening for AFib by this method compared favorably with the area-under-the-curve (AUC) results tallied by several widely accepted screening tools, including Pap smears for cervical cancer (AUC of 0.70), mammograms for breast cancer (AUC of 0.85), and CHA2DS2-VASc scoring for estimating stroke risk in AFib patients (AUC of 0.57-0.72), Dr. Friedman said.
The researchers developed the AI algorithm with more than 450,000 10-second ECG tracings collected from roughly 126,000 patients who underwent at least one ECG recording as part of their routine care at the Mayo Clinic during 1993-2017. The goal was for the program to find and validate recurring characteristics in the ECG that consistently linked with a history of or an impending AFib episode and that did not appear in ECG recordings from people without any AFib history. The program this effort produced then underwent further adjustment with the use of more than 64,340 ECGs from an additional 18,116 patients, and then the final product underwent validation testing with a further 130,802 ECGs collected from an additional 36,280 people, the study phase that resulted in the reported sensitivity and specificity estimates.
It’s currently unclear to Dr. Friedman and associates what specific features the program uses to classify patients. It’s an important question, but if the results are reproducible and reliable, this uncertainty shouldn’t slow clinical adoption, he said in an interview.
While “this particular algorithm needs prospective vetting,” a similar algorithm developed by Dr. Friedman and the same research team that uses a 10-second ECG to identify patients with a left ventricular ejection fraction of 35% or less is further advanced in development, and a device that uses this algorithm will soon receive Food and Drug Administration review under a fast track designation that the agency approved in late 2019.
The researchers developed this algorithm for estimating left ventricular function using a strategy similar to their development of a tool for diagnosing AFib (Nat Med. 2019 Jan 7;25[1]:70-4), and results from 100 patients prospectively studied with this approach to ECG analysis and reported at the American Heart Association scientific sessions in November 2019 showed that the algorithm identified substantial left ventricular dysfunction with an AUC of 0.906 (Circulation. 2019 Nov 19;140[suppl 1]:A13447). The same team of investigators has developed an AI algorithm that can calculate a person’s physiologic age based on the ECG recording (Circ Arrhythm Electrophysiol. 2019 Sep;12[9]: 10.1161/CIRCEP.119.007284).
The study received no commercial funding, and Dr. Friedman and coauthors had no relevant disclosures. The Mayo Clinic has licensed a related artificial intelligence algorithm to EKO, and Dr. Friedman may benefit financially from this arrangement.
THE AF SYMPOSIUM 2020
Pulsed field catheter ablation shows huge clinical promise for AFib
NATIONAL HARBOR, MD. – Cardiac electrophysiologists have reported using pulsed field ablation, a new power source for catheter ablation of atrial fibrillation, on fewer than 150 patients worldwide in initial clinical studies, but its performance so far and the promise it carries for substantially improving the safety and efficacy of catheter ablation has convinced many experts that it represents the future for this intervention.
“I’m very excited about PFA [pulsed field ablation]. It may make everything else obsolete,” Andrea Natale, MD, said at the annual International AF Symposium. “We need to see more efficacy data, but just for safety alone there is no reason to use anything else,” commented Dr. Natale, executive medical director of the Texas Cardiac Arrhythmia Institute at St. David’s Medical Center in Austin,Tex.
“The main issue is safety, and if PFA lives up to its promise, then [using it preferentially] is not a difficult decision,” commented Francis E. Marchlinski, MD, professor of medicine and director of electrophysiology at the University of Pennsylvania.
“The only question is whether it has good long-term efficacy” because so far no patients have been followed for longer than about a year after PFA treatment, noted Moussa Mansour, MD, director of the cardiac electrophysiology laboratory at Massachusetts General Hospital in Boston. “If that piece turns out to be true, then I think it will be a winner.”
Vivek Y. Reddy, MD, one of the few investigators to have already collaborated on clinical studies that used PFA to catheter ablate both in patients with paroxysmal and, more recently, persistent atrial fibrillation (AFib), put it this way: “I’m 99% sure” PFA will be the energy of choice in the near future for AFib catheter ablation. The 1% of uncertainty “is only because of what might be unknown, something we’re not expecting,” said Dr. Reddy, professor of medicine and director of the cardiac arrhythmia service at Mount Sinai Medical Center in New York.
He and his associates at a center in Prague and at a second site in Bordeaux, France, reported their collective experience in 2019 regarding use of PFA on 81 patients with symptomatic, paroxysmal AFib who had not responded to at least one antiarrhythmic drug (J Am Coll Cardiol. 2019 Jul;74[3]:315-26). During a session on PFA at the symposium, Pierre Jaïs, MD, a cardiac electrophysiologist and professor of cardiology at the University of Bordeaux, updated this experience to now include 113 patients treated by the end of 2019 at the same two centers plus now an added third site, an experience accumulated by a total of five operators. Fifty-one patients have now been followed for at least a year, with no “unexpected” safety events, said Dr. Jaïs, The most recent 88 patients underwent PFA without general anesthesia. The ablation technique has undergone several refinements during this experience, and with use of the most recent, biphasic protocol that’s so far treated 26 patients, 24 (92%) of the treated patients had no reconnected AFib circuits in their atrial tissue when they underwent remapping 3 months after their procedure.
Magnetic resonance imaging of the left atria of these patients after pulmonary vein isolation with PFA showed a uniquely homogeneous and continuous lesion that functionally isolated each vein from surrounding atrial tissue and denoted a more uniform and complete ablation, Dr. Jaïs noted. “I have never seen [an ablation] as homogeneous.” The Magnetic resonance pictures also showed that the esophagus in each treated patient remained completely undamaged. “Esophageal sparing is systematically observed,” along with phrenic nerve sparing that’s in notable contrast with what’s seen with conventional energy sources, he said. The images also indicated that edema was substantially reduced compared with both radiofrequency and cryoablation, while mechanical function of treated left atria has consistently been “well preserved.”
“For the first time, we can use extra power to ensure durable lesions without compromising safety,” Dr. Jaïs concluded. PFA appears to put AFib ablation “on the verge of a totally new era.”
The less extensive and briefer experience in patients with persistent AFib has been completely consistent. This included 25 patients who had not responded to at least one antiarrhythmic drug treated by either of two operators, one in Prague and the other in Split, Croatia. All 25 patients who underwent pulmonary vein isolation had the procedure successfully completed as assessed with acute mapping of arrhythmia circuits after ablation, and the 24 of these patients who also underwent posterior wall ablation with the PFA device all had a successful acute result according to mapping, Dr. Reddy reported. No patient had an adverse event. PFA treatments were relatively fast, with an average procedure time in this series of 132 minutes. Repeat mapping 3 months after treatment is still pending.
At the heart of PFA’s safety is its “myocardial selectivity” which has so far kept PFA from causing any esophageal or phrenic nerve injuries, two potential complications of conventional AFib catheter ablation with use of either radiofrequency or cryo energy. Dr. Reddy was quick to highlight that there is no absolute selectivity for myocardium. “If you create a big enough field, it will electroporate everything, but the margin [between safety and damage] seems wide enough to take advantage” of focally damaging myocardial tissue in the left atrium to disrupt arrhythmia circuits while sparing adjacent tissue. Irreversible electroporation is the means by which PFA destroys targets cells while leaving other tissue unscathed, and a precisely adjusted PFA signal can focus its lethal effect exclusively on myocardial cells, a feature of PFA that Dr. Reddy called “lucky.”
The pulsed field ablation studies have been sponsored by Farapulse, the company developing this device, which in May 2019 received breakthrough designation for priority review from the Food and Drug Administration.
Dr. Reddy and Dr. Jaïs are both consultants to and shareholders in Farapulse. Dr. Natale has received honoraria from or has been a consultant to Biotronik, Janssen, Medtronic, and St. Jude. Dr. Marchlinski has been a consultant to or has received honoraria from Abbott EP/St. Jude, Biotronik, and Medtronic. Dr. Mansour has been a consultant for Abbott and Medtronic, has an equity interest or stock options in NewPace and EPD Solutions, and has received research grants from Abbott, Boehringer Ingelheim, Pfizer, and Sentre Heart. In addition, all sources have received consulting fees, honoraria, and/or research grants from Biosense Webster and Boston Scientific.
NATIONAL HARBOR, MD. – Cardiac electrophysiologists have reported using pulsed field ablation, a new power source for catheter ablation of atrial fibrillation, on fewer than 150 patients worldwide in initial clinical studies, but its performance so far and the promise it carries for substantially improving the safety and efficacy of catheter ablation has convinced many experts that it represents the future for this intervention.
“I’m very excited about PFA [pulsed field ablation]. It may make everything else obsolete,” Andrea Natale, MD, said at the annual International AF Symposium. “We need to see more efficacy data, but just for safety alone there is no reason to use anything else,” commented Dr. Natale, executive medical director of the Texas Cardiac Arrhythmia Institute at St. David’s Medical Center in Austin,Tex.
“The main issue is safety, and if PFA lives up to its promise, then [using it preferentially] is not a difficult decision,” commented Francis E. Marchlinski, MD, professor of medicine and director of electrophysiology at the University of Pennsylvania.
“The only question is whether it has good long-term efficacy” because so far no patients have been followed for longer than about a year after PFA treatment, noted Moussa Mansour, MD, director of the cardiac electrophysiology laboratory at Massachusetts General Hospital in Boston. “If that piece turns out to be true, then I think it will be a winner.”
Vivek Y. Reddy, MD, one of the few investigators to have already collaborated on clinical studies that used PFA to catheter ablate both in patients with paroxysmal and, more recently, persistent atrial fibrillation (AFib), put it this way: “I’m 99% sure” PFA will be the energy of choice in the near future for AFib catheter ablation. The 1% of uncertainty “is only because of what might be unknown, something we’re not expecting,” said Dr. Reddy, professor of medicine and director of the cardiac arrhythmia service at Mount Sinai Medical Center in New York.
He and his associates at a center in Prague and at a second site in Bordeaux, France, reported their collective experience in 2019 regarding use of PFA on 81 patients with symptomatic, paroxysmal AFib who had not responded to at least one antiarrhythmic drug (J Am Coll Cardiol. 2019 Jul;74[3]:315-26). During a session on PFA at the symposium, Pierre Jaïs, MD, a cardiac electrophysiologist and professor of cardiology at the University of Bordeaux, updated this experience to now include 113 patients treated by the end of 2019 at the same two centers plus now an added third site, an experience accumulated by a total of five operators. Fifty-one patients have now been followed for at least a year, with no “unexpected” safety events, said Dr. Jaïs, The most recent 88 patients underwent PFA without general anesthesia. The ablation technique has undergone several refinements during this experience, and with use of the most recent, biphasic protocol that’s so far treated 26 patients, 24 (92%) of the treated patients had no reconnected AFib circuits in their atrial tissue when they underwent remapping 3 months after their procedure.
Magnetic resonance imaging of the left atria of these patients after pulmonary vein isolation with PFA showed a uniquely homogeneous and continuous lesion that functionally isolated each vein from surrounding atrial tissue and denoted a more uniform and complete ablation, Dr. Jaïs noted. “I have never seen [an ablation] as homogeneous.” The Magnetic resonance pictures also showed that the esophagus in each treated patient remained completely undamaged. “Esophageal sparing is systematically observed,” along with phrenic nerve sparing that’s in notable contrast with what’s seen with conventional energy sources, he said. The images also indicated that edema was substantially reduced compared with both radiofrequency and cryoablation, while mechanical function of treated left atria has consistently been “well preserved.”
“For the first time, we can use extra power to ensure durable lesions without compromising safety,” Dr. Jaïs concluded. PFA appears to put AFib ablation “on the verge of a totally new era.”
The less extensive and briefer experience in patients with persistent AFib has been completely consistent. This included 25 patients who had not responded to at least one antiarrhythmic drug treated by either of two operators, one in Prague and the other in Split, Croatia. All 25 patients who underwent pulmonary vein isolation had the procedure successfully completed as assessed with acute mapping of arrhythmia circuits after ablation, and the 24 of these patients who also underwent posterior wall ablation with the PFA device all had a successful acute result according to mapping, Dr. Reddy reported. No patient had an adverse event. PFA treatments were relatively fast, with an average procedure time in this series of 132 minutes. Repeat mapping 3 months after treatment is still pending.
At the heart of PFA’s safety is its “myocardial selectivity” which has so far kept PFA from causing any esophageal or phrenic nerve injuries, two potential complications of conventional AFib catheter ablation with use of either radiofrequency or cryo energy. Dr. Reddy was quick to highlight that there is no absolute selectivity for myocardium. “If you create a big enough field, it will electroporate everything, but the margin [between safety and damage] seems wide enough to take advantage” of focally damaging myocardial tissue in the left atrium to disrupt arrhythmia circuits while sparing adjacent tissue. Irreversible electroporation is the means by which PFA destroys targets cells while leaving other tissue unscathed, and a precisely adjusted PFA signal can focus its lethal effect exclusively on myocardial cells, a feature of PFA that Dr. Reddy called “lucky.”
The pulsed field ablation studies have been sponsored by Farapulse, the company developing this device, which in May 2019 received breakthrough designation for priority review from the Food and Drug Administration.
Dr. Reddy and Dr. Jaïs are both consultants to and shareholders in Farapulse. Dr. Natale has received honoraria from or has been a consultant to Biotronik, Janssen, Medtronic, and St. Jude. Dr. Marchlinski has been a consultant to or has received honoraria from Abbott EP/St. Jude, Biotronik, and Medtronic. Dr. Mansour has been a consultant for Abbott and Medtronic, has an equity interest or stock options in NewPace and EPD Solutions, and has received research grants from Abbott, Boehringer Ingelheim, Pfizer, and Sentre Heart. In addition, all sources have received consulting fees, honoraria, and/or research grants from Biosense Webster and Boston Scientific.
NATIONAL HARBOR, MD. – Cardiac electrophysiologists have reported using pulsed field ablation, a new power source for catheter ablation of atrial fibrillation, on fewer than 150 patients worldwide in initial clinical studies, but its performance so far and the promise it carries for substantially improving the safety and efficacy of catheter ablation has convinced many experts that it represents the future for this intervention.
“I’m very excited about PFA [pulsed field ablation]. It may make everything else obsolete,” Andrea Natale, MD, said at the annual International AF Symposium. “We need to see more efficacy data, but just for safety alone there is no reason to use anything else,” commented Dr. Natale, executive medical director of the Texas Cardiac Arrhythmia Institute at St. David’s Medical Center in Austin,Tex.
“The main issue is safety, and if PFA lives up to its promise, then [using it preferentially] is not a difficult decision,” commented Francis E. Marchlinski, MD, professor of medicine and director of electrophysiology at the University of Pennsylvania.
“The only question is whether it has good long-term efficacy” because so far no patients have been followed for longer than about a year after PFA treatment, noted Moussa Mansour, MD, director of the cardiac electrophysiology laboratory at Massachusetts General Hospital in Boston. “If that piece turns out to be true, then I think it will be a winner.”
Vivek Y. Reddy, MD, one of the few investigators to have already collaborated on clinical studies that used PFA to catheter ablate both in patients with paroxysmal and, more recently, persistent atrial fibrillation (AFib), put it this way: “I’m 99% sure” PFA will be the energy of choice in the near future for AFib catheter ablation. The 1% of uncertainty “is only because of what might be unknown, something we’re not expecting,” said Dr. Reddy, professor of medicine and director of the cardiac arrhythmia service at Mount Sinai Medical Center in New York.
He and his associates at a center in Prague and at a second site in Bordeaux, France, reported their collective experience in 2019 regarding use of PFA on 81 patients with symptomatic, paroxysmal AFib who had not responded to at least one antiarrhythmic drug (J Am Coll Cardiol. 2019 Jul;74[3]:315-26). During a session on PFA at the symposium, Pierre Jaïs, MD, a cardiac electrophysiologist and professor of cardiology at the University of Bordeaux, updated this experience to now include 113 patients treated by the end of 2019 at the same two centers plus now an added third site, an experience accumulated by a total of five operators. Fifty-one patients have now been followed for at least a year, with no “unexpected” safety events, said Dr. Jaïs, The most recent 88 patients underwent PFA without general anesthesia. The ablation technique has undergone several refinements during this experience, and with use of the most recent, biphasic protocol that’s so far treated 26 patients, 24 (92%) of the treated patients had no reconnected AFib circuits in their atrial tissue when they underwent remapping 3 months after their procedure.
Magnetic resonance imaging of the left atria of these patients after pulmonary vein isolation with PFA showed a uniquely homogeneous and continuous lesion that functionally isolated each vein from surrounding atrial tissue and denoted a more uniform and complete ablation, Dr. Jaïs noted. “I have never seen [an ablation] as homogeneous.” The Magnetic resonance pictures also showed that the esophagus in each treated patient remained completely undamaged. “Esophageal sparing is systematically observed,” along with phrenic nerve sparing that’s in notable contrast with what’s seen with conventional energy sources, he said. The images also indicated that edema was substantially reduced compared with both radiofrequency and cryoablation, while mechanical function of treated left atria has consistently been “well preserved.”
“For the first time, we can use extra power to ensure durable lesions without compromising safety,” Dr. Jaïs concluded. PFA appears to put AFib ablation “on the verge of a totally new era.”
The less extensive and briefer experience in patients with persistent AFib has been completely consistent. This included 25 patients who had not responded to at least one antiarrhythmic drug treated by either of two operators, one in Prague and the other in Split, Croatia. All 25 patients who underwent pulmonary vein isolation had the procedure successfully completed as assessed with acute mapping of arrhythmia circuits after ablation, and the 24 of these patients who also underwent posterior wall ablation with the PFA device all had a successful acute result according to mapping, Dr. Reddy reported. No patient had an adverse event. PFA treatments were relatively fast, with an average procedure time in this series of 132 minutes. Repeat mapping 3 months after treatment is still pending.
At the heart of PFA’s safety is its “myocardial selectivity” which has so far kept PFA from causing any esophageal or phrenic nerve injuries, two potential complications of conventional AFib catheter ablation with use of either radiofrequency or cryo energy. Dr. Reddy was quick to highlight that there is no absolute selectivity for myocardium. “If you create a big enough field, it will electroporate everything, but the margin [between safety and damage] seems wide enough to take advantage” of focally damaging myocardial tissue in the left atrium to disrupt arrhythmia circuits while sparing adjacent tissue. Irreversible electroporation is the means by which PFA destroys targets cells while leaving other tissue unscathed, and a precisely adjusted PFA signal can focus its lethal effect exclusively on myocardial cells, a feature of PFA that Dr. Reddy called “lucky.”
The pulsed field ablation studies have been sponsored by Farapulse, the company developing this device, which in May 2019 received breakthrough designation for priority review from the Food and Drug Administration.
Dr. Reddy and Dr. Jaïs are both consultants to and shareholders in Farapulse. Dr. Natale has received honoraria from or has been a consultant to Biotronik, Janssen, Medtronic, and St. Jude. Dr. Marchlinski has been a consultant to or has received honoraria from Abbott EP/St. Jude, Biotronik, and Medtronic. Dr. Mansour has been a consultant for Abbott and Medtronic, has an equity interest or stock options in NewPace and EPD Solutions, and has received research grants from Abbott, Boehringer Ingelheim, Pfizer, and Sentre Heart. In addition, all sources have received consulting fees, honoraria, and/or research grants from Biosense Webster and Boston Scientific.
EXPERT ANALYSIS FROM THE AF SYMPOSIUM 2020
Heart rhythm data from wearables confounds EP practice
NATIONAL HARBOR, MD. – or other warnings that flagged a possible cardiac arrhythmia.
While the clinical community has yet to reach an evidence-based consensus on how to deal with this information, or even asymptomatic arrhythmias identified by more standard means, the American public is voting with their wrists. People seem to like collecting and reviewing readouts on their heart rhythm and other vital data, and then they often take their numbers to a physician, especially when their device suggests a possible problem.
“The whole paradigm of ordering a test only if you intend to act on the result has been flipped. People now get what they want directly, and our job is to guide them” after the fact. “You need to teach people what’s actionable and what’s not,” Mintu P. Turakhia, MD, said at the annual International AF Symposium.
“We’re in a situation where the ability of a sensor to detect things is separate from access to the health care system. They are no longer coupled; they are disjointed. People can create their own ICU in their house just by shopping online, but what do we do with this information, whether it’s an irregular heart rhythm or their whole genome?” asked Dr. Turakhia, executive director of the Center for Digital Health at Stanford (Calif.) University and director of cardiac electrophysiology at the VA Palo Alto (Calif.) Health Care System.
“The main challenge is people without a diagnosis who get a notification. How much monitoring should you do until you can say it was a false positive? We don’t know what to do, so we monitor them. People are trying to figure this out.” Dr. Turakhia said. Some people who seek out electrophysiologists this way “may not even have a primary care physician,” he noted.
The potential implications of widespread monitoring for heartbeat irregularities in the general public began to surface in a study that Dr. Turakhia helped run that collected wearable data from nearly 420,000 Americans. Results from the Apple Heart Study showed that, during a median 117 days of monitoring with a smart watch, 2,161 people (0.5%) received a report of an irregular pulse, which led to further investigations that eventually diagnosed atrial fibrillation (AFib) in 153 people of the 450 who underwent follow-up assessment (N Engl J Med. 2019 Nov 14;381[20]:1909-17). These results “raise questions” about the large number of people who underwent follow-up testing who did not have arrhythmia, Dr. Turakhia noted.
“The dissemination of wearables has been quite dramatic, and electrophysiologists end up owning this,” commented Jeremy N. Ruskin, MD, professor of medicine at Harvard Medical School and director emeritus of the cardiac arrhythmia service at Massachusetts General Hospital, both in Boston. “I get a ton of calls from people whom I wish never bought a smart watch, and they say ‘I have atrial fibrillation. What do I do?’ ”
To document the growth of this trend, Dr. Turakhia cited results from a survey he collaborated on, run by Stanford and Rock Health, that found a 33% ownership rate among American adults of a wearable device capable of collecting health data, and a 42% rate of people who tracked their health data with a device, app, journal, or log. Both of these rates more than doubled what a similar survey found in 2015.
The cardiac electrophysiology community took a first step toward addressing one aspect of this evolving situation. In early 2020, the Heart Rhythm Society and the Consumer Technology Association jointly issued a guidance document targeted at consumers that walks them through the kinds of information their wearable devices might collect and how to approach this information. The main message: If you have questions or concerns about your data, consult a clinician. What remains in short supply is guidance to clinicians on what to do when they see these patients.
“Until recently, device-detected AFib was the sole purview of electrophysiologists using implanted rhythm-monitoring devices. Now mobile and other devices raise issues [of asymptomatic AFib] for a much broader population,” noted Daniel E. Singer, MD, professor of medicine and epidemiology at Harvard and Massachusetts General Hospital. “The world of device-detected AFib now includes watches.”
Researchers have tried for years to better understand the stroke risk faced by patients with asymptomatic or subclinical AFib that’s detected by an implanted device, as in the ASSERT study of nearly 2,600 patients followed for a median of 2.5 years that found an increased stroke risk when the duration of individual, subclinical AFib episodes surpassed 24 hours (Eur Heart J. 2017 May 1;38[17]:1339-44). More recently, a study of AFib duration collected by implanted cardiac devices in nearly 22,000 Americans showed a relationship between stroke risk and both the duration of AFib episodes and the underlying risk of a person for stroke as measured by their CHA2DS2-VAScscore (Circulation. 2019 Nov 12;140[20]:1639-46). Just under 30% of patients in the study were diagnosed with AFib at entry.
The implications of asymptomatic episodes of AFib have so far been largely studied in people with an implanted cardiac device, which may have limited applicability to wearable users. In addition, the field has not yet fully sorted out the relationships between the duration of individual AFib episodes and overall AFib burden, and a person’s stroke risk and the window of time when the potential stroke-preventing benefits of anticoagulation outweigh its bleeding risk.
The results of trials now in progress that are examining the safety and efficacy of medical interventions designed to avert strokes in patients with asymptomatic AFib “will bear on the use of anticoagulants in a large group of patients,” including people with AFib detected by a wearable, Dr. Singer predicted.
The Apple Heart Study was sponsored Apple. Dr. Turakhia has received funding from Apple, and he has received honoraria or research funding from several other companies. Dr. Ruskin has been a consultant or adviser to several companies, is a steering committee member for Pfizer, and holds equity or options in Portola, Element Science, NewPace, Gilead, and InfoBionic. Dr. Singer has been a consultant and adviser to Boehringer Ingelheim, Bristol-Myers Squibb, Johnson & Johnson, Merck, and Pfizer, and he has received research grants from Bristol-Myers Squibb.
NATIONAL HARBOR, MD. – or other warnings that flagged a possible cardiac arrhythmia.
While the clinical community has yet to reach an evidence-based consensus on how to deal with this information, or even asymptomatic arrhythmias identified by more standard means, the American public is voting with their wrists. People seem to like collecting and reviewing readouts on their heart rhythm and other vital data, and then they often take their numbers to a physician, especially when their device suggests a possible problem.
“The whole paradigm of ordering a test only if you intend to act on the result has been flipped. People now get what they want directly, and our job is to guide them” after the fact. “You need to teach people what’s actionable and what’s not,” Mintu P. Turakhia, MD, said at the annual International AF Symposium.
“We’re in a situation where the ability of a sensor to detect things is separate from access to the health care system. They are no longer coupled; they are disjointed. People can create their own ICU in their house just by shopping online, but what do we do with this information, whether it’s an irregular heart rhythm or their whole genome?” asked Dr. Turakhia, executive director of the Center for Digital Health at Stanford (Calif.) University and director of cardiac electrophysiology at the VA Palo Alto (Calif.) Health Care System.
“The main challenge is people without a diagnosis who get a notification. How much monitoring should you do until you can say it was a false positive? We don’t know what to do, so we monitor them. People are trying to figure this out.” Dr. Turakhia said. Some people who seek out electrophysiologists this way “may not even have a primary care physician,” he noted.
The potential implications of widespread monitoring for heartbeat irregularities in the general public began to surface in a study that Dr. Turakhia helped run that collected wearable data from nearly 420,000 Americans. Results from the Apple Heart Study showed that, during a median 117 days of monitoring with a smart watch, 2,161 people (0.5%) received a report of an irregular pulse, which led to further investigations that eventually diagnosed atrial fibrillation (AFib) in 153 people of the 450 who underwent follow-up assessment (N Engl J Med. 2019 Nov 14;381[20]:1909-17). These results “raise questions” about the large number of people who underwent follow-up testing who did not have arrhythmia, Dr. Turakhia noted.
“The dissemination of wearables has been quite dramatic, and electrophysiologists end up owning this,” commented Jeremy N. Ruskin, MD, professor of medicine at Harvard Medical School and director emeritus of the cardiac arrhythmia service at Massachusetts General Hospital, both in Boston. “I get a ton of calls from people whom I wish never bought a smart watch, and they say ‘I have atrial fibrillation. What do I do?’ ”
To document the growth of this trend, Dr. Turakhia cited results from a survey he collaborated on, run by Stanford and Rock Health, that found a 33% ownership rate among American adults of a wearable device capable of collecting health data, and a 42% rate of people who tracked their health data with a device, app, journal, or log. Both of these rates more than doubled what a similar survey found in 2015.
The cardiac electrophysiology community took a first step toward addressing one aspect of this evolving situation. In early 2020, the Heart Rhythm Society and the Consumer Technology Association jointly issued a guidance document targeted at consumers that walks them through the kinds of information their wearable devices might collect and how to approach this information. The main message: If you have questions or concerns about your data, consult a clinician. What remains in short supply is guidance to clinicians on what to do when they see these patients.
“Until recently, device-detected AFib was the sole purview of electrophysiologists using implanted rhythm-monitoring devices. Now mobile and other devices raise issues [of asymptomatic AFib] for a much broader population,” noted Daniel E. Singer, MD, professor of medicine and epidemiology at Harvard and Massachusetts General Hospital. “The world of device-detected AFib now includes watches.”
Researchers have tried for years to better understand the stroke risk faced by patients with asymptomatic or subclinical AFib that’s detected by an implanted device, as in the ASSERT study of nearly 2,600 patients followed for a median of 2.5 years that found an increased stroke risk when the duration of individual, subclinical AFib episodes surpassed 24 hours (Eur Heart J. 2017 May 1;38[17]:1339-44). More recently, a study of AFib duration collected by implanted cardiac devices in nearly 22,000 Americans showed a relationship between stroke risk and both the duration of AFib episodes and the underlying risk of a person for stroke as measured by their CHA2DS2-VAScscore (Circulation. 2019 Nov 12;140[20]:1639-46). Just under 30% of patients in the study were diagnosed with AFib at entry.
The implications of asymptomatic episodes of AFib have so far been largely studied in people with an implanted cardiac device, which may have limited applicability to wearable users. In addition, the field has not yet fully sorted out the relationships between the duration of individual AFib episodes and overall AFib burden, and a person’s stroke risk and the window of time when the potential stroke-preventing benefits of anticoagulation outweigh its bleeding risk.
The results of trials now in progress that are examining the safety and efficacy of medical interventions designed to avert strokes in patients with asymptomatic AFib “will bear on the use of anticoagulants in a large group of patients,” including people with AFib detected by a wearable, Dr. Singer predicted.
The Apple Heart Study was sponsored Apple. Dr. Turakhia has received funding from Apple, and he has received honoraria or research funding from several other companies. Dr. Ruskin has been a consultant or adviser to several companies, is a steering committee member for Pfizer, and holds equity or options in Portola, Element Science, NewPace, Gilead, and InfoBionic. Dr. Singer has been a consultant and adviser to Boehringer Ingelheim, Bristol-Myers Squibb, Johnson & Johnson, Merck, and Pfizer, and he has received research grants from Bristol-Myers Squibb.
NATIONAL HARBOR, MD. – or other warnings that flagged a possible cardiac arrhythmia.
While the clinical community has yet to reach an evidence-based consensus on how to deal with this information, or even asymptomatic arrhythmias identified by more standard means, the American public is voting with their wrists. People seem to like collecting and reviewing readouts on their heart rhythm and other vital data, and then they often take their numbers to a physician, especially when their device suggests a possible problem.
“The whole paradigm of ordering a test only if you intend to act on the result has been flipped. People now get what they want directly, and our job is to guide them” after the fact. “You need to teach people what’s actionable and what’s not,” Mintu P. Turakhia, MD, said at the annual International AF Symposium.
“We’re in a situation where the ability of a sensor to detect things is separate from access to the health care system. They are no longer coupled; they are disjointed. People can create their own ICU in their house just by shopping online, but what do we do with this information, whether it’s an irregular heart rhythm or their whole genome?” asked Dr. Turakhia, executive director of the Center for Digital Health at Stanford (Calif.) University and director of cardiac electrophysiology at the VA Palo Alto (Calif.) Health Care System.
“The main challenge is people without a diagnosis who get a notification. How much monitoring should you do until you can say it was a false positive? We don’t know what to do, so we monitor them. People are trying to figure this out.” Dr. Turakhia said. Some people who seek out electrophysiologists this way “may not even have a primary care physician,” he noted.
The potential implications of widespread monitoring for heartbeat irregularities in the general public began to surface in a study that Dr. Turakhia helped run that collected wearable data from nearly 420,000 Americans. Results from the Apple Heart Study showed that, during a median 117 days of monitoring with a smart watch, 2,161 people (0.5%) received a report of an irregular pulse, which led to further investigations that eventually diagnosed atrial fibrillation (AFib) in 153 people of the 450 who underwent follow-up assessment (N Engl J Med. 2019 Nov 14;381[20]:1909-17). These results “raise questions” about the large number of people who underwent follow-up testing who did not have arrhythmia, Dr. Turakhia noted.
“The dissemination of wearables has been quite dramatic, and electrophysiologists end up owning this,” commented Jeremy N. Ruskin, MD, professor of medicine at Harvard Medical School and director emeritus of the cardiac arrhythmia service at Massachusetts General Hospital, both in Boston. “I get a ton of calls from people whom I wish never bought a smart watch, and they say ‘I have atrial fibrillation. What do I do?’ ”
To document the growth of this trend, Dr. Turakhia cited results from a survey he collaborated on, run by Stanford and Rock Health, that found a 33% ownership rate among American adults of a wearable device capable of collecting health data, and a 42% rate of people who tracked their health data with a device, app, journal, or log. Both of these rates more than doubled what a similar survey found in 2015.
The cardiac electrophysiology community took a first step toward addressing one aspect of this evolving situation. In early 2020, the Heart Rhythm Society and the Consumer Technology Association jointly issued a guidance document targeted at consumers that walks them through the kinds of information their wearable devices might collect and how to approach this information. The main message: If you have questions or concerns about your data, consult a clinician. What remains in short supply is guidance to clinicians on what to do when they see these patients.
“Until recently, device-detected AFib was the sole purview of electrophysiologists using implanted rhythm-monitoring devices. Now mobile and other devices raise issues [of asymptomatic AFib] for a much broader population,” noted Daniel E. Singer, MD, professor of medicine and epidemiology at Harvard and Massachusetts General Hospital. “The world of device-detected AFib now includes watches.”
Researchers have tried for years to better understand the stroke risk faced by patients with asymptomatic or subclinical AFib that’s detected by an implanted device, as in the ASSERT study of nearly 2,600 patients followed for a median of 2.5 years that found an increased stroke risk when the duration of individual, subclinical AFib episodes surpassed 24 hours (Eur Heart J. 2017 May 1;38[17]:1339-44). More recently, a study of AFib duration collected by implanted cardiac devices in nearly 22,000 Americans showed a relationship between stroke risk and both the duration of AFib episodes and the underlying risk of a person for stroke as measured by their CHA2DS2-VAScscore (Circulation. 2019 Nov 12;140[20]:1639-46). Just under 30% of patients in the study were diagnosed with AFib at entry.
The implications of asymptomatic episodes of AFib have so far been largely studied in people with an implanted cardiac device, which may have limited applicability to wearable users. In addition, the field has not yet fully sorted out the relationships between the duration of individual AFib episodes and overall AFib burden, and a person’s stroke risk and the window of time when the potential stroke-preventing benefits of anticoagulation outweigh its bleeding risk.
The results of trials now in progress that are examining the safety and efficacy of medical interventions designed to avert strokes in patients with asymptomatic AFib “will bear on the use of anticoagulants in a large group of patients,” including people with AFib detected by a wearable, Dr. Singer predicted.
The Apple Heart Study was sponsored Apple. Dr. Turakhia has received funding from Apple, and he has received honoraria or research funding from several other companies. Dr. Ruskin has been a consultant or adviser to several companies, is a steering committee member for Pfizer, and holds equity or options in Portola, Element Science, NewPace, Gilead, and InfoBionic. Dr. Singer has been a consultant and adviser to Boehringer Ingelheim, Bristol-Myers Squibb, Johnson & Johnson, Merck, and Pfizer, and he has received research grants from Bristol-Myers Squibb.
REPORTING FROM THE AF SYMPOSIUM 2020
Vigilance safely keeps AFib patients off anticoagulants post ablation
NATIONAL HARBOR, MD. – A pilot program of daily arrhythmia self-vigilance has allowed selected patients with no atrial fibrillation following a catheter ablation procedure to safely come off a regimen of daily oral anticoagulation despite having residual risk factors for ischemic stroke.
This program, which started several years ago at the University of Pennsylvania in Philadelphia, has now managed 190 patients and followed them for a median of just over 3 years, and during 576 patient-years of follow-up, just a single patient had an ischemic cerebrovascular event that occurred with no atrial fibrillation (AFib) recurrence and appeared to be caused by an atherosclerotic embolism, Francis E. Marchlinski, MD, said at the annual International AF Symposium.
Although this strategy has not yet been tested in a prospective, randomized trial, this anecdotal, single-center experience suggests that the approach is “safe and effective” for selected patients who are eager to come off of their anticoagulation regimen when they remain arrhythmia free following catheter ablation of their AFib, said Dr. Marchlinski, professor of medicine and director of electrophysiology at the University of Pennsylvania. He and his associates developed this strategy as a way to more safely allow these patients to stop taking a daily oral anticoagulant because he found that many patients were stopping on their own, with no safety strategy in place.
“Patients tell me they don’t want to be on an oral anticoagulant because a parent had a hemorrhagic stroke, and they say they’re willing to accept the risk” of having an ischemic stroke by coming off anticoagulation. “This is a way for them to do it safely,” Dr. Marchlinski said in an interview. He stressed that he only allows his patients to go this route if they understand the risk and accept their shared responsibility for vigilant, twice-daily pulse monitoring to detect resumption of an irregular heart beat.
Since 2011, Dr. Marchlinski’s program ablated 1,216 patients with AFib who then remained arrhythmia free during 3 weeks of continuous ECG monitoring following their procedure. Among these patients, 443 had a CHA2DS2-VAScscore of either 0 (men) or 1 (women) that indicated no ongoing need for oral anticoagulation according to current guidelines. Of the remaining 773 patients with a CHA2DS2-VASc score of at least 1 in men and 2 in women, the clinicians determined 583 to be ineligible for the program because of their unwillingness to accept the risk, unwillingness to comply with daily pulse checks, a history of asymptomatic AFib, a CHA2DS2-VASc score greater than 4, or a resting pulse above 90 beats per minute, leaving 190 patients eligible to participate. Among these patients, 105 (55%) had a CHA2DS2-VASc score of 2-4, which should prompt anticoagulation according to current guidelines.Participating patients committed to check their resting pulse by palpation at least twice daily and to contacting the program immediately if their resting rate spiked by more than 20 beats per minutes or in another way seemed irregular. Patients were also instructed to restart their oral anticoagulation immediately if they experienced AFib symptoms that persisted for more than 5 minutes. Many patients in the program also use a wearable device (usually a watch) to monitor their resting pulse and to generate a 30-second ECG recording that they can send as an electronic file to the University of Pennsylvania staff. “We embrace wearables,” Dr. Marchlinski said. Those without a wearable can undergo transtelephonic EEG monitoring to document a suspected arrhythmia recurrence, and all patients undergo annual monitoring by continuous ECG for at least 2 weeks.During follow-up, in addition to the 1 patient free from recurrent AFib who had an atherosclerotic embolism, 34 patients resumed anticoagulant treatment because of AFib recurrence; 12 withdrew from the program because of noncompliance or preference, or because an exclusion appeared; 29 resumed oral anticoagulation transiently but then discontinued the drug a second time when their AFib recurrence resolved; and 114 patients (60% of the starting cohort of 190) remained completely off anticoagulation during a median of 37 months. These data updated a published report from Dr. Marchlinski and his associates on their first 99 patients followed for a median of 30 months (J Cardiovasc Electrophysiol. 2019 May;30[5]:631-8).
This experience underscored the need for ongoing rhythm monitoring even in the absence of AFib symptoms, as six patients developed asymptomatic AFib detected by monitoring, including one patient whose recurrence occurred 30 months after the ablation procedure.
Dr. Marchlinski stressed the stringent selection process he applies to limit this approach to patients who are willing to faithfully monitor their pulse and symptoms daily, and who accept the risk that this approach may pose and their responsibility to stay in contact with the clinical team. The program calls patients at the 6-month mark between annual monitoring to remind them of their need for daily attention.
“Being off anticoagulants is very important to these patients,” he explained, and he highlighted the added workload this strategy places on his staff. “I think this has legs” for adoption by other cardiac arrhythmia programs, “but it depends on the time the staff is willing to spend” monitoring and following these patients, some of whom regularly send in ECG traces from their wearable devices for assessment. “It takes a village” to make this program work, he said.
Dr. Marchlinski has been a consultant to or has received honoraria from Abbott EP/St. Jude, Biosense Webster, Biotronik, Boston Scientific, and Medtronic.
NATIONAL HARBOR, MD. – A pilot program of daily arrhythmia self-vigilance has allowed selected patients with no atrial fibrillation following a catheter ablation procedure to safely come off a regimen of daily oral anticoagulation despite having residual risk factors for ischemic stroke.
This program, which started several years ago at the University of Pennsylvania in Philadelphia, has now managed 190 patients and followed them for a median of just over 3 years, and during 576 patient-years of follow-up, just a single patient had an ischemic cerebrovascular event that occurred with no atrial fibrillation (AFib) recurrence and appeared to be caused by an atherosclerotic embolism, Francis E. Marchlinski, MD, said at the annual International AF Symposium.
Although this strategy has not yet been tested in a prospective, randomized trial, this anecdotal, single-center experience suggests that the approach is “safe and effective” for selected patients who are eager to come off of their anticoagulation regimen when they remain arrhythmia free following catheter ablation of their AFib, said Dr. Marchlinski, professor of medicine and director of electrophysiology at the University of Pennsylvania. He and his associates developed this strategy as a way to more safely allow these patients to stop taking a daily oral anticoagulant because he found that many patients were stopping on their own, with no safety strategy in place.
“Patients tell me they don’t want to be on an oral anticoagulant because a parent had a hemorrhagic stroke, and they say they’re willing to accept the risk” of having an ischemic stroke by coming off anticoagulation. “This is a way for them to do it safely,” Dr. Marchlinski said in an interview. He stressed that he only allows his patients to go this route if they understand the risk and accept their shared responsibility for vigilant, twice-daily pulse monitoring to detect resumption of an irregular heart beat.
Since 2011, Dr. Marchlinski’s program ablated 1,216 patients with AFib who then remained arrhythmia free during 3 weeks of continuous ECG monitoring following their procedure. Among these patients, 443 had a CHA2DS2-VAScscore of either 0 (men) or 1 (women) that indicated no ongoing need for oral anticoagulation according to current guidelines. Of the remaining 773 patients with a CHA2DS2-VASc score of at least 1 in men and 2 in women, the clinicians determined 583 to be ineligible for the program because of their unwillingness to accept the risk, unwillingness to comply with daily pulse checks, a history of asymptomatic AFib, a CHA2DS2-VASc score greater than 4, or a resting pulse above 90 beats per minute, leaving 190 patients eligible to participate. Among these patients, 105 (55%) had a CHA2DS2-VASc score of 2-4, which should prompt anticoagulation according to current guidelines.Participating patients committed to check their resting pulse by palpation at least twice daily and to contacting the program immediately if their resting rate spiked by more than 20 beats per minutes or in another way seemed irregular. Patients were also instructed to restart their oral anticoagulation immediately if they experienced AFib symptoms that persisted for more than 5 minutes. Many patients in the program also use a wearable device (usually a watch) to monitor their resting pulse and to generate a 30-second ECG recording that they can send as an electronic file to the University of Pennsylvania staff. “We embrace wearables,” Dr. Marchlinski said. Those without a wearable can undergo transtelephonic EEG monitoring to document a suspected arrhythmia recurrence, and all patients undergo annual monitoring by continuous ECG for at least 2 weeks.During follow-up, in addition to the 1 patient free from recurrent AFib who had an atherosclerotic embolism, 34 patients resumed anticoagulant treatment because of AFib recurrence; 12 withdrew from the program because of noncompliance or preference, or because an exclusion appeared; 29 resumed oral anticoagulation transiently but then discontinued the drug a second time when their AFib recurrence resolved; and 114 patients (60% of the starting cohort of 190) remained completely off anticoagulation during a median of 37 months. These data updated a published report from Dr. Marchlinski and his associates on their first 99 patients followed for a median of 30 months (J Cardiovasc Electrophysiol. 2019 May;30[5]:631-8).
This experience underscored the need for ongoing rhythm monitoring even in the absence of AFib symptoms, as six patients developed asymptomatic AFib detected by monitoring, including one patient whose recurrence occurred 30 months after the ablation procedure.
Dr. Marchlinski stressed the stringent selection process he applies to limit this approach to patients who are willing to faithfully monitor their pulse and symptoms daily, and who accept the risk that this approach may pose and their responsibility to stay in contact with the clinical team. The program calls patients at the 6-month mark between annual monitoring to remind them of their need for daily attention.
“Being off anticoagulants is very important to these patients,” he explained, and he highlighted the added workload this strategy places on his staff. “I think this has legs” for adoption by other cardiac arrhythmia programs, “but it depends on the time the staff is willing to spend” monitoring and following these patients, some of whom regularly send in ECG traces from their wearable devices for assessment. “It takes a village” to make this program work, he said.
Dr. Marchlinski has been a consultant to or has received honoraria from Abbott EP/St. Jude, Biosense Webster, Biotronik, Boston Scientific, and Medtronic.
NATIONAL HARBOR, MD. – A pilot program of daily arrhythmia self-vigilance has allowed selected patients with no atrial fibrillation following a catheter ablation procedure to safely come off a regimen of daily oral anticoagulation despite having residual risk factors for ischemic stroke.
This program, which started several years ago at the University of Pennsylvania in Philadelphia, has now managed 190 patients and followed them for a median of just over 3 years, and during 576 patient-years of follow-up, just a single patient had an ischemic cerebrovascular event that occurred with no atrial fibrillation (AFib) recurrence and appeared to be caused by an atherosclerotic embolism, Francis E. Marchlinski, MD, said at the annual International AF Symposium.
Although this strategy has not yet been tested in a prospective, randomized trial, this anecdotal, single-center experience suggests that the approach is “safe and effective” for selected patients who are eager to come off of their anticoagulation regimen when they remain arrhythmia free following catheter ablation of their AFib, said Dr. Marchlinski, professor of medicine and director of electrophysiology at the University of Pennsylvania. He and his associates developed this strategy as a way to more safely allow these patients to stop taking a daily oral anticoagulant because he found that many patients were stopping on their own, with no safety strategy in place.
“Patients tell me they don’t want to be on an oral anticoagulant because a parent had a hemorrhagic stroke, and they say they’re willing to accept the risk” of having an ischemic stroke by coming off anticoagulation. “This is a way for them to do it safely,” Dr. Marchlinski said in an interview. He stressed that he only allows his patients to go this route if they understand the risk and accept their shared responsibility for vigilant, twice-daily pulse monitoring to detect resumption of an irregular heart beat.
Since 2011, Dr. Marchlinski’s program ablated 1,216 patients with AFib who then remained arrhythmia free during 3 weeks of continuous ECG monitoring following their procedure. Among these patients, 443 had a CHA2DS2-VAScscore of either 0 (men) or 1 (women) that indicated no ongoing need for oral anticoagulation according to current guidelines. Of the remaining 773 patients with a CHA2DS2-VASc score of at least 1 in men and 2 in women, the clinicians determined 583 to be ineligible for the program because of their unwillingness to accept the risk, unwillingness to comply with daily pulse checks, a history of asymptomatic AFib, a CHA2DS2-VASc score greater than 4, or a resting pulse above 90 beats per minute, leaving 190 patients eligible to participate. Among these patients, 105 (55%) had a CHA2DS2-VASc score of 2-4, which should prompt anticoagulation according to current guidelines.Participating patients committed to check their resting pulse by palpation at least twice daily and to contacting the program immediately if their resting rate spiked by more than 20 beats per minutes or in another way seemed irregular. Patients were also instructed to restart their oral anticoagulation immediately if they experienced AFib symptoms that persisted for more than 5 minutes. Many patients in the program also use a wearable device (usually a watch) to monitor their resting pulse and to generate a 30-second ECG recording that they can send as an electronic file to the University of Pennsylvania staff. “We embrace wearables,” Dr. Marchlinski said. Those without a wearable can undergo transtelephonic EEG monitoring to document a suspected arrhythmia recurrence, and all patients undergo annual monitoring by continuous ECG for at least 2 weeks.During follow-up, in addition to the 1 patient free from recurrent AFib who had an atherosclerotic embolism, 34 patients resumed anticoagulant treatment because of AFib recurrence; 12 withdrew from the program because of noncompliance or preference, or because an exclusion appeared; 29 resumed oral anticoagulation transiently but then discontinued the drug a second time when their AFib recurrence resolved; and 114 patients (60% of the starting cohort of 190) remained completely off anticoagulation during a median of 37 months. These data updated a published report from Dr. Marchlinski and his associates on their first 99 patients followed for a median of 30 months (J Cardiovasc Electrophysiol. 2019 May;30[5]:631-8).
This experience underscored the need for ongoing rhythm monitoring even in the absence of AFib symptoms, as six patients developed asymptomatic AFib detected by monitoring, including one patient whose recurrence occurred 30 months after the ablation procedure.
Dr. Marchlinski stressed the stringent selection process he applies to limit this approach to patients who are willing to faithfully monitor their pulse and symptoms daily, and who accept the risk that this approach may pose and their responsibility to stay in contact with the clinical team. The program calls patients at the 6-month mark between annual monitoring to remind them of their need for daily attention.
“Being off anticoagulants is very important to these patients,” he explained, and he highlighted the added workload this strategy places on his staff. “I think this has legs” for adoption by other cardiac arrhythmia programs, “but it depends on the time the staff is willing to spend” monitoring and following these patients, some of whom regularly send in ECG traces from their wearable devices for assessment. “It takes a village” to make this program work, he said.
Dr. Marchlinski has been a consultant to or has received honoraria from Abbott EP/St. Jude, Biosense Webster, Biotronik, Boston Scientific, and Medtronic.
REPORTING FROM THE AF SYMPOSIUM 2020
Catheter cryoablation effective for persistent AFib in pivotal trial
NATIONAL HARBOR, MD. – , setting the stage for the device to become the first to receive U.S. labeling for catheter ablation in this atrial fibrillation population.
The Arctic Front Advance cryoballoon, used on 165 patients with persistent atrial fibrillation (AFib) enrolled in the trial, produced a 55% rate of treatment success, including freedom from recurrent AFib during 12 months of follow-up, and produced one prespecified serious adverse event in the primary safety endpoint.
Both results easily surpassed the prespecified performance goals set by negotiation with the FDA, Hugh Calkins, MD, said at the annual International AF Symposium. The trial design included no control group and instead assessed safety and efficacy against prespecified standards set by the regulatory agency.
The cryoballoon “showed excellent performance. I don’t see how this could possibly be turned down by the FDA,” said Dr. Calkins, professor of medicine and director of the cardiac arrhythmia service at Johns Hopkins Medicine in Baltimore.
Cardiac electrophysiologists have for years routinely performed catheter ablation procedures on patients with persistent AFib even though the devices, based on ablation by radiofrequency or by chilling, have been labeled for use only in treating patients with paroxysmal AFib. Although this off-label use has not resulted in any problems with health insurance coverage, Dr. Calkins said, it has kept manufacturers from marketing their ablation devices for use in persistent AFib patients.
If the reported data result in labeling for the tested cryoballoon for persistant AFib patients, “it will have a big impact,” he predicted. “People have used cryoballoons for ablating persistent AFib for years, but this would put more fuel in the fire, both the [very positive] safety and efficacy data, and getting an FDA label, which is worth a lot,” he said in an interview.
But Dr. Calkins stopped short of anticipating that the results would convince operators experienced and focused on performing radiofrequency ablation to switch to cryo devices for treating persistent AFib patients. “People are pretty stuck in their ways,” he noted, and reports are expected soon from pivotal trials that are now testing various radiofrequency devices, as well as other types of cryo devices, in persistent AFib patients, so the range of device options labeled for this population may soon grow even more.
The STOP Persistent AF trial ran at 25 sites in the United States, Canada, and Japan during March 2017-August 2019, and included 165 adults with symptomatic, persistent AFib who had not responded to at least one antiarrhythmic drug and had a history of AFib episodes lasting at least 7 days but with no episodes persisting for 6 months or longer. The study excluded patients with prior ablation or left atrial surgery, a recent cerebrovascular event, substantially reduced left ventricular function, or substantial left atrial enlargement.
The enrolled patients were an average 65 years of age and 70% were men. Patients had been diagnosed with paroxysmal AFib an average of 5 years before study entry and with persistent AFib a little over 6 months before entry. The most recent AFib episode of enrolled patients averaged about 60 days, on average they had been unsuccessfully treated with just over one antiarrhythmic drug, and on average they had previously undergone about two cardioversions, after which their arrhythmia recurred.
The primary efficacy endpoint – a 55% rate of acute procedural success plus freedom from AFib recurrence during the 9 months following a 90-day blanking period immediately after ablation plus no added or increased antiarrhythmic drugs – significantly exceeded the prespecified performance goal of a 40% rate, Dr. Calkins reported. The study used the standard measure of recurrence as any 30-second or longer AFib episode detected during a weekly ECG telemonitoring session or during 48-hour ambulatory ECG monitoring at 6- and 12-month follow-ups or during in-office 12-lead ECG assessment at 3-, 6-, and 12-month follow-up. Twelve-month follow-up occurred for 145 of the enrolled patients.
The only prespecified primary safety event was one episode of cardiac perforation, which occurred during a repeat procedure. This rate of one safety event among 165 patients (0.6%) fell well within the prespecified safety performance goal of no more than 13%. In addition to this perforation, five additional serious adverse events (3%) occurred that were attributable to the cryoballoon treatment, including two cases of vascular pseudoaneurysm, one puncture-site hematoma, one case of pericarditis, and one episode of atrial tachycardia. Four additional serious adverse events occurred that were attributable to the ablation procedure (one acute cardiac failure, one postprocedure ileus, one respiratory failure, and one urinary tract infection), for an overall serious event rate of 5%.
During follow-up, 13% of patients had a repeat ablation procedure, following an initial ablation limited to pulmonary-vein isolation (PVI). The overall rate of 1-year efficacy, including the relatively low rate of need for redo ablation, “are an impressive endorsement of a PVI-only strategy” for initial ablation, Dr. Calkins said. “I’m a strong believer in PVI only for the first ablation for both paroxysmal and persistent AFib.”
He also noted that the 30-second threshold for scoring recurrent arrhythmia episodes following the 90-day blanking period after ablation was a very conservative measure of treatment failure, but it continues to define recurrence in this and many other current AFib ablation studies because it is the historical criteria for measuring ablation success or failure. It is especially important to maintain this criteria in a study that relied on prespecified performance criteria rather than a control arm for judging efficacy, Dr. Calkins said.
The study also included three quality-of-life measures. Patient scores on the Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaire rose by an average of nearly 26 points from baseline to 12 months, a statistically significant and clinically meaningful increase. Scores on both the physical and mental domains of the Short Form-12 (SF-12) improved from baseline by an average of about five points on each subscale, also statistically significant and clinically meaningful changes. Patients also reported statistically significant and in some cases substantial reductions in the prevalence rates of each of five different AFib symptoms: dizziness, dyspnea, fatigue, palpitations, and rapid heartbeat.
The study was funded by Medtronic, the company that markets the tested cryoballoon (Arctic Front Advance). Dr. Calkins has been a consultant to and has received honoraria from Medtronic, as well as from Abbott, AtriCure, Boehringer Ingelheim, Boston Scientific, and Johnson & Johnson.
NATIONAL HARBOR, MD. – , setting the stage for the device to become the first to receive U.S. labeling for catheter ablation in this atrial fibrillation population.
The Arctic Front Advance cryoballoon, used on 165 patients with persistent atrial fibrillation (AFib) enrolled in the trial, produced a 55% rate of treatment success, including freedom from recurrent AFib during 12 months of follow-up, and produced one prespecified serious adverse event in the primary safety endpoint.
Both results easily surpassed the prespecified performance goals set by negotiation with the FDA, Hugh Calkins, MD, said at the annual International AF Symposium. The trial design included no control group and instead assessed safety and efficacy against prespecified standards set by the regulatory agency.
The cryoballoon “showed excellent performance. I don’t see how this could possibly be turned down by the FDA,” said Dr. Calkins, professor of medicine and director of the cardiac arrhythmia service at Johns Hopkins Medicine in Baltimore.
Cardiac electrophysiologists have for years routinely performed catheter ablation procedures on patients with persistent AFib even though the devices, based on ablation by radiofrequency or by chilling, have been labeled for use only in treating patients with paroxysmal AFib. Although this off-label use has not resulted in any problems with health insurance coverage, Dr. Calkins said, it has kept manufacturers from marketing their ablation devices for use in persistent AFib patients.
If the reported data result in labeling for the tested cryoballoon for persistant AFib patients, “it will have a big impact,” he predicted. “People have used cryoballoons for ablating persistent AFib for years, but this would put more fuel in the fire, both the [very positive] safety and efficacy data, and getting an FDA label, which is worth a lot,” he said in an interview.
But Dr. Calkins stopped short of anticipating that the results would convince operators experienced and focused on performing radiofrequency ablation to switch to cryo devices for treating persistent AFib patients. “People are pretty stuck in their ways,” he noted, and reports are expected soon from pivotal trials that are now testing various radiofrequency devices, as well as other types of cryo devices, in persistent AFib patients, so the range of device options labeled for this population may soon grow even more.
The STOP Persistent AF trial ran at 25 sites in the United States, Canada, and Japan during March 2017-August 2019, and included 165 adults with symptomatic, persistent AFib who had not responded to at least one antiarrhythmic drug and had a history of AFib episodes lasting at least 7 days but with no episodes persisting for 6 months or longer. The study excluded patients with prior ablation or left atrial surgery, a recent cerebrovascular event, substantially reduced left ventricular function, or substantial left atrial enlargement.
The enrolled patients were an average 65 years of age and 70% were men. Patients had been diagnosed with paroxysmal AFib an average of 5 years before study entry and with persistent AFib a little over 6 months before entry. The most recent AFib episode of enrolled patients averaged about 60 days, on average they had been unsuccessfully treated with just over one antiarrhythmic drug, and on average they had previously undergone about two cardioversions, after which their arrhythmia recurred.
The primary efficacy endpoint – a 55% rate of acute procedural success plus freedom from AFib recurrence during the 9 months following a 90-day blanking period immediately after ablation plus no added or increased antiarrhythmic drugs – significantly exceeded the prespecified performance goal of a 40% rate, Dr. Calkins reported. The study used the standard measure of recurrence as any 30-second or longer AFib episode detected during a weekly ECG telemonitoring session or during 48-hour ambulatory ECG monitoring at 6- and 12-month follow-ups or during in-office 12-lead ECG assessment at 3-, 6-, and 12-month follow-up. Twelve-month follow-up occurred for 145 of the enrolled patients.
The only prespecified primary safety event was one episode of cardiac perforation, which occurred during a repeat procedure. This rate of one safety event among 165 patients (0.6%) fell well within the prespecified safety performance goal of no more than 13%. In addition to this perforation, five additional serious adverse events (3%) occurred that were attributable to the cryoballoon treatment, including two cases of vascular pseudoaneurysm, one puncture-site hematoma, one case of pericarditis, and one episode of atrial tachycardia. Four additional serious adverse events occurred that were attributable to the ablation procedure (one acute cardiac failure, one postprocedure ileus, one respiratory failure, and one urinary tract infection), for an overall serious event rate of 5%.
During follow-up, 13% of patients had a repeat ablation procedure, following an initial ablation limited to pulmonary-vein isolation (PVI). The overall rate of 1-year efficacy, including the relatively low rate of need for redo ablation, “are an impressive endorsement of a PVI-only strategy” for initial ablation, Dr. Calkins said. “I’m a strong believer in PVI only for the first ablation for both paroxysmal and persistent AFib.”
He also noted that the 30-second threshold for scoring recurrent arrhythmia episodes following the 90-day blanking period after ablation was a very conservative measure of treatment failure, but it continues to define recurrence in this and many other current AFib ablation studies because it is the historical criteria for measuring ablation success or failure. It is especially important to maintain this criteria in a study that relied on prespecified performance criteria rather than a control arm for judging efficacy, Dr. Calkins said.
The study also included three quality-of-life measures. Patient scores on the Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaire rose by an average of nearly 26 points from baseline to 12 months, a statistically significant and clinically meaningful increase. Scores on both the physical and mental domains of the Short Form-12 (SF-12) improved from baseline by an average of about five points on each subscale, also statistically significant and clinically meaningful changes. Patients also reported statistically significant and in some cases substantial reductions in the prevalence rates of each of five different AFib symptoms: dizziness, dyspnea, fatigue, palpitations, and rapid heartbeat.
The study was funded by Medtronic, the company that markets the tested cryoballoon (Arctic Front Advance). Dr. Calkins has been a consultant to and has received honoraria from Medtronic, as well as from Abbott, AtriCure, Boehringer Ingelheim, Boston Scientific, and Johnson & Johnson.
NATIONAL HARBOR, MD. – , setting the stage for the device to become the first to receive U.S. labeling for catheter ablation in this atrial fibrillation population.
The Arctic Front Advance cryoballoon, used on 165 patients with persistent atrial fibrillation (AFib) enrolled in the trial, produced a 55% rate of treatment success, including freedom from recurrent AFib during 12 months of follow-up, and produced one prespecified serious adverse event in the primary safety endpoint.
Both results easily surpassed the prespecified performance goals set by negotiation with the FDA, Hugh Calkins, MD, said at the annual International AF Symposium. The trial design included no control group and instead assessed safety and efficacy against prespecified standards set by the regulatory agency.
The cryoballoon “showed excellent performance. I don’t see how this could possibly be turned down by the FDA,” said Dr. Calkins, professor of medicine and director of the cardiac arrhythmia service at Johns Hopkins Medicine in Baltimore.
Cardiac electrophysiologists have for years routinely performed catheter ablation procedures on patients with persistent AFib even though the devices, based on ablation by radiofrequency or by chilling, have been labeled for use only in treating patients with paroxysmal AFib. Although this off-label use has not resulted in any problems with health insurance coverage, Dr. Calkins said, it has kept manufacturers from marketing their ablation devices for use in persistent AFib patients.
If the reported data result in labeling for the tested cryoballoon for persistant AFib patients, “it will have a big impact,” he predicted. “People have used cryoballoons for ablating persistent AFib for years, but this would put more fuel in the fire, both the [very positive] safety and efficacy data, and getting an FDA label, which is worth a lot,” he said in an interview.
But Dr. Calkins stopped short of anticipating that the results would convince operators experienced and focused on performing radiofrequency ablation to switch to cryo devices for treating persistent AFib patients. “People are pretty stuck in their ways,” he noted, and reports are expected soon from pivotal trials that are now testing various radiofrequency devices, as well as other types of cryo devices, in persistent AFib patients, so the range of device options labeled for this population may soon grow even more.
The STOP Persistent AF trial ran at 25 sites in the United States, Canada, and Japan during March 2017-August 2019, and included 165 adults with symptomatic, persistent AFib who had not responded to at least one antiarrhythmic drug and had a history of AFib episodes lasting at least 7 days but with no episodes persisting for 6 months or longer. The study excluded patients with prior ablation or left atrial surgery, a recent cerebrovascular event, substantially reduced left ventricular function, or substantial left atrial enlargement.
The enrolled patients were an average 65 years of age and 70% were men. Patients had been diagnosed with paroxysmal AFib an average of 5 years before study entry and with persistent AFib a little over 6 months before entry. The most recent AFib episode of enrolled patients averaged about 60 days, on average they had been unsuccessfully treated with just over one antiarrhythmic drug, and on average they had previously undergone about two cardioversions, after which their arrhythmia recurred.
The primary efficacy endpoint – a 55% rate of acute procedural success plus freedom from AFib recurrence during the 9 months following a 90-day blanking period immediately after ablation plus no added or increased antiarrhythmic drugs – significantly exceeded the prespecified performance goal of a 40% rate, Dr. Calkins reported. The study used the standard measure of recurrence as any 30-second or longer AFib episode detected during a weekly ECG telemonitoring session or during 48-hour ambulatory ECG monitoring at 6- and 12-month follow-ups or during in-office 12-lead ECG assessment at 3-, 6-, and 12-month follow-up. Twelve-month follow-up occurred for 145 of the enrolled patients.
The only prespecified primary safety event was one episode of cardiac perforation, which occurred during a repeat procedure. This rate of one safety event among 165 patients (0.6%) fell well within the prespecified safety performance goal of no more than 13%. In addition to this perforation, five additional serious adverse events (3%) occurred that were attributable to the cryoballoon treatment, including two cases of vascular pseudoaneurysm, one puncture-site hematoma, one case of pericarditis, and one episode of atrial tachycardia. Four additional serious adverse events occurred that were attributable to the ablation procedure (one acute cardiac failure, one postprocedure ileus, one respiratory failure, and one urinary tract infection), for an overall serious event rate of 5%.
During follow-up, 13% of patients had a repeat ablation procedure, following an initial ablation limited to pulmonary-vein isolation (PVI). The overall rate of 1-year efficacy, including the relatively low rate of need for redo ablation, “are an impressive endorsement of a PVI-only strategy” for initial ablation, Dr. Calkins said. “I’m a strong believer in PVI only for the first ablation for both paroxysmal and persistent AFib.”
He also noted that the 30-second threshold for scoring recurrent arrhythmia episodes following the 90-day blanking period after ablation was a very conservative measure of treatment failure, but it continues to define recurrence in this and many other current AFib ablation studies because it is the historical criteria for measuring ablation success or failure. It is especially important to maintain this criteria in a study that relied on prespecified performance criteria rather than a control arm for judging efficacy, Dr. Calkins said.
The study also included three quality-of-life measures. Patient scores on the Atrial Fibrillation Effect on Quality-of-Life (AFEQT) questionnaire rose by an average of nearly 26 points from baseline to 12 months, a statistically significant and clinically meaningful increase. Scores on both the physical and mental domains of the Short Form-12 (SF-12) improved from baseline by an average of about five points on each subscale, also statistically significant and clinically meaningful changes. Patients also reported statistically significant and in some cases substantial reductions in the prevalence rates of each of five different AFib symptoms: dizziness, dyspnea, fatigue, palpitations, and rapid heartbeat.
The study was funded by Medtronic, the company that markets the tested cryoballoon (Arctic Front Advance). Dr. Calkins has been a consultant to and has received honoraria from Medtronic, as well as from Abbott, AtriCure, Boehringer Ingelheim, Boston Scientific, and Johnson & Johnson.
REPORTING FROM THE AF SYMPOSIUM 2020
Key clinical point: Catheter ablation using a cryoballoon was safe and effective for patients with persistent atrial fibrillation in a pivotal trial.
Major finding: The rate of freedom from treatment failure after 12 months was 55%, significantly exceeding the prespecified performance goal of 40%.
Study details: A multicenter, international study with 165 enrolled patients.
Disclosures: The study was funded by Medtronic, the company that markets the tested cryoballoon (Arctic Front Advance). Dr. Calkins has been a consultant to and has received honoraria from Medtronic, as well as from Abbott, AtriCure, Boehringer Ingelheim, Boston Scientific, and Johnson & Johnson.
AFib link with titin mutations warrants selected genetic testing
NATIONAL HARBOR, MD. – Testing to identify mutations in the gene that codes for the muscle protein titin is now a reasonable step in routine clinical practice for selected people with either early-onset atrial fibrillation (AFib) or a family history of atrial fibrillation, or other cardiac disorders that have been strongly linked with titin-gene mutations, Patrick T. Ellinor, MD, said at the annual International AF Symposium.
About one out of every 250 people carries a loss of function (LOF) mutation in one of their TTN genes that codes for the titin protein, making these mutations about as common as mutations for familial hypercholesterolemia, noted Dr. Ellinor, professor of medicine at Harvard Medical School in Boston and director of the Cardiovascular Disease Initiative at the Broad Institute in Cambridge, Mass. TTN LOF mutations are “bad and very frequent,” he said in an interview. “This is evolving quickly as we start to appreciate how frequent these mutations are.”
Several commercial genetic testing companies now offer testing of blood specimens for TTN LOF mutations, often as part of an “arrhythmia test” panel, with a turnaround time of about 4 weeks at a cost to the patient of about $100, noted Dr. Ellinor, who said that he has begun to discuss such testing with a small number of patients in his practice. “It’s reasonable for selected people; the jury is still out on which ones,” a subject that guideline writers will soon need to address, he said.
Patients already diagnosed with early-onset atrial fibrillation (AFib) could benefit from knowing if they had a TTN LOF mutation because that diagnosis would warrant a magnetic resonance scan to look for “subtle myopathies” not detectable with echocardiography, Dr. Ellinor explained. Identification of a TTN LOF would also be a reason to then test the patient’s children. “Perhaps we should offer testing to everyone 40 years old or younger with AFib,” Dr. Ellinor suggested. Many of these patients are now getting genetic testing for TTN on their own “whether or not their physician wants it done,” he noted.
The most recent, and perhaps most persuasive evidence for the link between TTN LOF mutations and AFib came from a recent report from Dr. Ellinor and associates that examined genome-wide associations in 1,546 people with AFib and 41,593 controls using information contained in the UK Biobank, which holds complete gene sequencing data for about half a million U.K. residents (Circ Res. 2020 Jan 17;126[2]: 200-9). The results showed that just under 0.5% of the entire population carried a TTN LOF mutation, and among patients with AFib the prevalence of a TTN LOF mutation was about 2%, but among people who carry this type of mutation 14% were diagnosed with AFib. This penetrance of 14% for AFib among people with a TTN LOF mutation makes AFib the most frequent clinical consequence identified so far for people with this type of mutation. Other cardiac disorders linked with TTN LOF mutations include heart failure and nonischemic cardiomyopathy. The Biobank study findings showed a penetrance for heart failure of about 7% among those with a TTN LOF mutation, and a penetrance of these mutations for nonischemic cardiomyopathy of about 3%.
Dr. Ellinor cited three other recently published studies with consistent results documenting a strong link between TTN LOF mutations and AFib: a study he worked on with lead author Seung H. Choi, Ph.D., and associates that ran an analysis on 2,781 AFib patients and 4,959 controls in a U.S. database of people who underwent whole-genome sequencing (JAMA. 2018 Dec 11; 320[22]:2354-64); a study of 24 Danish families with clusters of three or more affected members with AFib as well as 399 Danish residents with lone, early-onset AFib (Nat Commun. 2018 Oct 17;9[1]:4316); and a study of 25 patients with “very early onset” (less than 45 years old) AFib, which identified four of the 25 patients with a TTN LOF mutation (Circ Genom Precis Med. 2019 Nov 12[11]; 526-8).
Titin is the largest protein in humans and is critical for normal myocardial function. Titin acts as a molecular scaffold for sarcomere assembly and signaling, providing passive stiffness to the sarcomere. Mutations in TTN have been associated with tibial muscular dystrophy, hypertrophic cardiomyopathy, and dilated cardiomyopathy. The relationship now established between TTN mutations and AFib, cardiomyopathy, and heart failure may in the future help explain the tight clinical association of AFib and heart failure, Dr. Ellinor noted. The TTN gene is also notable as the largest gene in the human genome.
Dr. Ellinor has received research funding from Bayer, and he has served as an adviser or consultant to Bayer, Quest Diagnostics, and Novartis.
SOURCE: Choi SH et al. Circ Res. 2020 Jan 17;126[2]: 200-9.
NATIONAL HARBOR, MD. – Testing to identify mutations in the gene that codes for the muscle protein titin is now a reasonable step in routine clinical practice for selected people with either early-onset atrial fibrillation (AFib) or a family history of atrial fibrillation, or other cardiac disorders that have been strongly linked with titin-gene mutations, Patrick T. Ellinor, MD, said at the annual International AF Symposium.
About one out of every 250 people carries a loss of function (LOF) mutation in one of their TTN genes that codes for the titin protein, making these mutations about as common as mutations for familial hypercholesterolemia, noted Dr. Ellinor, professor of medicine at Harvard Medical School in Boston and director of the Cardiovascular Disease Initiative at the Broad Institute in Cambridge, Mass. TTN LOF mutations are “bad and very frequent,” he said in an interview. “This is evolving quickly as we start to appreciate how frequent these mutations are.”
Several commercial genetic testing companies now offer testing of blood specimens for TTN LOF mutations, often as part of an “arrhythmia test” panel, with a turnaround time of about 4 weeks at a cost to the patient of about $100, noted Dr. Ellinor, who said that he has begun to discuss such testing with a small number of patients in his practice. “It’s reasonable for selected people; the jury is still out on which ones,” a subject that guideline writers will soon need to address, he said.
Patients already diagnosed with early-onset atrial fibrillation (AFib) could benefit from knowing if they had a TTN LOF mutation because that diagnosis would warrant a magnetic resonance scan to look for “subtle myopathies” not detectable with echocardiography, Dr. Ellinor explained. Identification of a TTN LOF would also be a reason to then test the patient’s children. “Perhaps we should offer testing to everyone 40 years old or younger with AFib,” Dr. Ellinor suggested. Many of these patients are now getting genetic testing for TTN on their own “whether or not their physician wants it done,” he noted.
The most recent, and perhaps most persuasive evidence for the link between TTN LOF mutations and AFib came from a recent report from Dr. Ellinor and associates that examined genome-wide associations in 1,546 people with AFib and 41,593 controls using information contained in the UK Biobank, which holds complete gene sequencing data for about half a million U.K. residents (Circ Res. 2020 Jan 17;126[2]: 200-9). The results showed that just under 0.5% of the entire population carried a TTN LOF mutation, and among patients with AFib the prevalence of a TTN LOF mutation was about 2%, but among people who carry this type of mutation 14% were diagnosed with AFib. This penetrance of 14% for AFib among people with a TTN LOF mutation makes AFib the most frequent clinical consequence identified so far for people with this type of mutation. Other cardiac disorders linked with TTN LOF mutations include heart failure and nonischemic cardiomyopathy. The Biobank study findings showed a penetrance for heart failure of about 7% among those with a TTN LOF mutation, and a penetrance of these mutations for nonischemic cardiomyopathy of about 3%.
Dr. Ellinor cited three other recently published studies with consistent results documenting a strong link between TTN LOF mutations and AFib: a study he worked on with lead author Seung H. Choi, Ph.D., and associates that ran an analysis on 2,781 AFib patients and 4,959 controls in a U.S. database of people who underwent whole-genome sequencing (JAMA. 2018 Dec 11; 320[22]:2354-64); a study of 24 Danish families with clusters of three or more affected members with AFib as well as 399 Danish residents with lone, early-onset AFib (Nat Commun. 2018 Oct 17;9[1]:4316); and a study of 25 patients with “very early onset” (less than 45 years old) AFib, which identified four of the 25 patients with a TTN LOF mutation (Circ Genom Precis Med. 2019 Nov 12[11]; 526-8).
Titin is the largest protein in humans and is critical for normal myocardial function. Titin acts as a molecular scaffold for sarcomere assembly and signaling, providing passive stiffness to the sarcomere. Mutations in TTN have been associated with tibial muscular dystrophy, hypertrophic cardiomyopathy, and dilated cardiomyopathy. The relationship now established between TTN mutations and AFib, cardiomyopathy, and heart failure may in the future help explain the tight clinical association of AFib and heart failure, Dr. Ellinor noted. The TTN gene is also notable as the largest gene in the human genome.
Dr. Ellinor has received research funding from Bayer, and he has served as an adviser or consultant to Bayer, Quest Diagnostics, and Novartis.
SOURCE: Choi SH et al. Circ Res. 2020 Jan 17;126[2]: 200-9.
NATIONAL HARBOR, MD. – Testing to identify mutations in the gene that codes for the muscle protein titin is now a reasonable step in routine clinical practice for selected people with either early-onset atrial fibrillation (AFib) or a family history of atrial fibrillation, or other cardiac disorders that have been strongly linked with titin-gene mutations, Patrick T. Ellinor, MD, said at the annual International AF Symposium.
About one out of every 250 people carries a loss of function (LOF) mutation in one of their TTN genes that codes for the titin protein, making these mutations about as common as mutations for familial hypercholesterolemia, noted Dr. Ellinor, professor of medicine at Harvard Medical School in Boston and director of the Cardiovascular Disease Initiative at the Broad Institute in Cambridge, Mass. TTN LOF mutations are “bad and very frequent,” he said in an interview. “This is evolving quickly as we start to appreciate how frequent these mutations are.”
Several commercial genetic testing companies now offer testing of blood specimens for TTN LOF mutations, often as part of an “arrhythmia test” panel, with a turnaround time of about 4 weeks at a cost to the patient of about $100, noted Dr. Ellinor, who said that he has begun to discuss such testing with a small number of patients in his practice. “It’s reasonable for selected people; the jury is still out on which ones,” a subject that guideline writers will soon need to address, he said.
Patients already diagnosed with early-onset atrial fibrillation (AFib) could benefit from knowing if they had a TTN LOF mutation because that diagnosis would warrant a magnetic resonance scan to look for “subtle myopathies” not detectable with echocardiography, Dr. Ellinor explained. Identification of a TTN LOF would also be a reason to then test the patient’s children. “Perhaps we should offer testing to everyone 40 years old or younger with AFib,” Dr. Ellinor suggested. Many of these patients are now getting genetic testing for TTN on their own “whether or not their physician wants it done,” he noted.
The most recent, and perhaps most persuasive evidence for the link between TTN LOF mutations and AFib came from a recent report from Dr. Ellinor and associates that examined genome-wide associations in 1,546 people with AFib and 41,593 controls using information contained in the UK Biobank, which holds complete gene sequencing data for about half a million U.K. residents (Circ Res. 2020 Jan 17;126[2]: 200-9). The results showed that just under 0.5% of the entire population carried a TTN LOF mutation, and among patients with AFib the prevalence of a TTN LOF mutation was about 2%, but among people who carry this type of mutation 14% were diagnosed with AFib. This penetrance of 14% for AFib among people with a TTN LOF mutation makes AFib the most frequent clinical consequence identified so far for people with this type of mutation. Other cardiac disorders linked with TTN LOF mutations include heart failure and nonischemic cardiomyopathy. The Biobank study findings showed a penetrance for heart failure of about 7% among those with a TTN LOF mutation, and a penetrance of these mutations for nonischemic cardiomyopathy of about 3%.
Dr. Ellinor cited three other recently published studies with consistent results documenting a strong link between TTN LOF mutations and AFib: a study he worked on with lead author Seung H. Choi, Ph.D., and associates that ran an analysis on 2,781 AFib patients and 4,959 controls in a U.S. database of people who underwent whole-genome sequencing (JAMA. 2018 Dec 11; 320[22]:2354-64); a study of 24 Danish families with clusters of three or more affected members with AFib as well as 399 Danish residents with lone, early-onset AFib (Nat Commun. 2018 Oct 17;9[1]:4316); and a study of 25 patients with “very early onset” (less than 45 years old) AFib, which identified four of the 25 patients with a TTN LOF mutation (Circ Genom Precis Med. 2019 Nov 12[11]; 526-8).
Titin is the largest protein in humans and is critical for normal myocardial function. Titin acts as a molecular scaffold for sarcomere assembly and signaling, providing passive stiffness to the sarcomere. Mutations in TTN have been associated with tibial muscular dystrophy, hypertrophic cardiomyopathy, and dilated cardiomyopathy. The relationship now established between TTN mutations and AFib, cardiomyopathy, and heart failure may in the future help explain the tight clinical association of AFib and heart failure, Dr. Ellinor noted. The TTN gene is also notable as the largest gene in the human genome.
Dr. Ellinor has received research funding from Bayer, and he has served as an adviser or consultant to Bayer, Quest Diagnostics, and Novartis.
SOURCE: Choi SH et al. Circ Res. 2020 Jan 17;126[2]: 200-9.
REPORTING FROM THE AF SYMPOSIUM 2020