Periodic repolarization dynamics may predict ICD outcomes

A novel marker of repolarization may identify patients with cardiomyopathy who would benefit from an implanted cardioverter defibrillator, according to a European research study presented at the annual congress of the European Society of Cardiology and published simultaneously in The Lancet.

High periodic repolarization dynamics were linked to substantial reductions in mortality in a prespecified substudy of the EU-CERT-ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter Defibrillators).

The degree of periodic repolarization dynamics correlated with reductions in mortality in the 1,371 patients, 968 of whom had ICD implantation and 403 of whom were treated conservatively, in the prospective, nonrandomized controlled cohort study conducted at 44 centers in 15 countries within the European Union. At a median follow-up of 2-7 years, the ICD group had a mortality rate of 14%; at a follow-up of 1-2 years, the control group had a mortality rate of 16%, resulting in a 43% overall reduction in mortality for the ICD group.

Low periodic repolarization dynamics were associated with a low reduction in ICD-related death, whereas high periodic repolarization dynamics were linked to substantial reductions in mortality. In 199 patients with periodic repolarization dynamics of 7.5% or higher, ICD implantation resulted in a 75% reduction in death, compared with controls. Periodic repolarization dynamics also served as reliable predictors of appropriate shocks in patients with ICDs as well as death in controls.

Because of the link between high periodic repolarization dynamics and greater benefits, cardiologists may be able to use the measure as a marker to individualize treatment decisions about the use of ICDs, said Axel Bauer, MD, director of University Hospital for Internal Medicine III, Cardiology and Angiology at Medical University Innsbruck, Austria, and coauthors. “Better patient selection could lead to a reduced number of devices needing to be implanted to save a life.

“Our results should help patients to make decisions about their treatment that take into account individual circumstances and preferences,” the researchers noted.

 

Their interest in periodic repolarization dynamics arises from increasing evidence that sympathetic mechanisms play a key role in malignant tachyarrhythmias (J Clin Invest. 2005;115:2305-15). They described periodic repolarization dynamics as a “marker of electric instability,” and noted that previous studies have shown a link between increased periodic repolarization dynamics and sudden cardiac death and adequate ICD interventions.

The study noted that more than 100,000 ICDs are implanted in the EU each year at a cost of €2 billion (U.S. $2.2 billion, Europace. 2017;19[suppl 2] ii1-90), but that a 2016 study showed that prophylactic ICD treatment may only benefit select patient subgroups (N Engl J Med. 2016;375:1221-30). While the EU-CERT-ICD supports primary prophylactic ICD therapy as the standard of care for patients with ischemic or nonischemic cardiomyopathy and reduced left ventricular ejection fraction, the invasive nature of ICD implantation carries with it risk of complications.

In an invited commentary, Sana M. Al-Khatib, MD, of Duke University, Durham, N.C., provided some context in interpreting the substudy results, noting, among other considerations, the study’s observational nature, exclusion of almost 40% of potentially eligible patients, and its omission of data for sudden cardiac death (Lancet. 2019 Sep 2. doi: 10.1016/S0140-6736[19]31956-7).

“Periodic repolarization dynamics are not yet ready for prime time,” Dr. Al-Khatib said. The group’s findings need to be validated by other studies, and a reproducible approach to measuring periodic repolarization dynamics should be established, he said. “Until such results are available, periodic repolarization dynamics are unlikely to gain traction as a test that can be consistently used to select patients for primary prevention of sudden cardiac death with ICDs.”

Dr. Bauer and Dr. Al-Khatib had no relevant financial relationships to disclose.

SOURCE: Bauer A et al. Lancet. 2019 Sep 2. doi: 10.1016/S0140-6736(19)31996-8.

A novel marker of repolarization may identify patients with cardiomyopathy who would benefit from an implanted cardioverter defibrillator, according to a European research study presented at the annual congress of the European Society of Cardiology and published simultaneously in The Lancet.

High periodic repolarization dynamics were linked to substantial reductions in mortality in a prespecified substudy of the EU-CERT-ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter Defibrillators).

The degree of periodic repolarization dynamics correlated with reductions in mortality in the 1,371 patients, 968 of whom had ICD implantation and 403 of whom were treated conservatively, in the prospective, nonrandomized controlled cohort study conducted at 44 centers in 15 countries within the European Union. At a median follow-up of 2-7 years, the ICD group had a mortality rate of 14%; at a follow-up of 1-2 years, the control group had a mortality rate of 16%, resulting in a 43% overall reduction in mortality for the ICD group.

Low periodic repolarization dynamics were associated with a low reduction in ICD-related death, whereas high periodic repolarization dynamics were linked to substantial reductions in mortality. In 199 patients with periodic repolarization dynamics of 7.5% or higher, ICD implantation resulted in a 75% reduction in death, compared with controls. Periodic repolarization dynamics also served as reliable predictors of appropriate shocks in patients with ICDs as well as death in controls.

Because of the link between high periodic repolarization dynamics and greater benefits, cardiologists may be able to use the measure as a marker to individualize treatment decisions about the use of ICDs, said Axel Bauer, MD, director of University Hospital for Internal Medicine III, Cardiology and Angiology at Medical University Innsbruck, Austria, and coauthors. “Better patient selection could lead to a reduced number of devices needing to be implanted to save a life.

“Our results should help patients to make decisions about their treatment that take into account individual circumstances and preferences,” the researchers noted.

 

Their interest in periodic repolarization dynamics arises from increasing evidence that sympathetic mechanisms play a key role in malignant tachyarrhythmias (J Clin Invest. 2005;115:2305-15). They described periodic repolarization dynamics as a “marker of electric instability,” and noted that previous studies have shown a link between increased periodic repolarization dynamics and sudden cardiac death and adequate ICD interventions.

The study noted that more than 100,000 ICDs are implanted in the EU each year at a cost of €2 billion (U.S. $2.2 billion, Europace. 2017;19[suppl 2] ii1-90), but that a 2016 study showed that prophylactic ICD treatment may only benefit select patient subgroups (N Engl J Med. 2016;375:1221-30). While the EU-CERT-ICD supports primary prophylactic ICD therapy as the standard of care for patients with ischemic or nonischemic cardiomyopathy and reduced left ventricular ejection fraction, the invasive nature of ICD implantation carries with it risk of complications.

In an invited commentary, Sana M. Al-Khatib, MD, of Duke University, Durham, N.C., provided some context in interpreting the substudy results, noting, among other considerations, the study’s observational nature, exclusion of almost 40% of potentially eligible patients, and its omission of data for sudden cardiac death (Lancet. 2019 Sep 2. doi: 10.1016/S0140-6736[19]31956-7).

“Periodic repolarization dynamics are not yet ready for prime time,” Dr. Al-Khatib said. The group’s findings need to be validated by other studies, and a reproducible approach to measuring periodic repolarization dynamics should be established, he said. “Until such results are available, periodic repolarization dynamics are unlikely to gain traction as a test that can be consistently used to select patients for primary prevention of sudden cardiac death with ICDs.”

Dr. Bauer and Dr. Al-Khatib had no relevant financial relationships to disclose.

SOURCE: Bauer A et al. Lancet. 2019 Sep 2. doi: 10.1016/S0140-6736(19)31996-8.

A novel marker of repolarization may identify patients with cardiomyopathy who would benefit from an implanted cardioverter defibrillator, according to a European research study presented at the annual congress of the European Society of Cardiology and published simultaneously in The Lancet.

High periodic repolarization dynamics were linked to substantial reductions in mortality in a prespecified substudy of the EU-CERT-ICD (European Comparative Effectiveness Research to Assess the Use of Primary Prophylactic Implantable Cardioverter Defibrillators).

The degree of periodic repolarization dynamics correlated with reductions in mortality in the 1,371 patients, 968 of whom had ICD implantation and 403 of whom were treated conservatively, in the prospective, nonrandomized controlled cohort study conducted at 44 centers in 15 countries within the European Union. At a median follow-up of 2-7 years, the ICD group had a mortality rate of 14%; at a follow-up of 1-2 years, the control group had a mortality rate of 16%, resulting in a 43% overall reduction in mortality for the ICD group.

Low periodic repolarization dynamics were associated with a low reduction in ICD-related death, whereas high periodic repolarization dynamics were linked to substantial reductions in mortality. In 199 patients with periodic repolarization dynamics of 7.5% or higher, ICD implantation resulted in a 75% reduction in death, compared with controls. Periodic repolarization dynamics also served as reliable predictors of appropriate shocks in patients with ICDs as well as death in controls.

Because of the link between high periodic repolarization dynamics and greater benefits, cardiologists may be able to use the measure as a marker to individualize treatment decisions about the use of ICDs, said Axel Bauer, MD, director of University Hospital for Internal Medicine III, Cardiology and Angiology at Medical University Innsbruck, Austria, and coauthors. “Better patient selection could lead to a reduced number of devices needing to be implanted to save a life.

“Our results should help patients to make decisions about their treatment that take into account individual circumstances and preferences,” the researchers noted.

 

Their interest in periodic repolarization dynamics arises from increasing evidence that sympathetic mechanisms play a key role in malignant tachyarrhythmias (J Clin Invest. 2005;115:2305-15). They described periodic repolarization dynamics as a “marker of electric instability,” and noted that previous studies have shown a link between increased periodic repolarization dynamics and sudden cardiac death and adequate ICD interventions.

The study noted that more than 100,000 ICDs are implanted in the EU each year at a cost of €2 billion (U.S. $2.2 billion, Europace. 2017;19[suppl 2] ii1-90), but that a 2016 study showed that prophylactic ICD treatment may only benefit select patient subgroups (N Engl J Med. 2016;375:1221-30). While the EU-CERT-ICD supports primary prophylactic ICD therapy as the standard of care for patients with ischemic or nonischemic cardiomyopathy and reduced left ventricular ejection fraction, the invasive nature of ICD implantation carries with it risk of complications.

In an invited commentary, Sana M. Al-Khatib, MD, of Duke University, Durham, N.C., provided some context in interpreting the substudy results, noting, among other considerations, the study’s observational nature, exclusion of almost 40% of potentially eligible patients, and its omission of data for sudden cardiac death (Lancet. 2019 Sep 2. doi: 10.1016/S0140-6736[19]31956-7).

“Periodic repolarization dynamics are not yet ready for prime time,” Dr. Al-Khatib said. The group’s findings need to be validated by other studies, and a reproducible approach to measuring periodic repolarization dynamics should be established, he said. “Until such results are available, periodic repolarization dynamics are unlikely to gain traction as a test that can be consistently used to select patients for primary prevention of sudden cardiac death with ICDs.”

Dr. Bauer and Dr. Al-Khatib had no relevant financial relationships to disclose.

SOURCE: Bauer A et al. Lancet. 2019 Sep 2. doi: 10.1016/S0140-6736(19)31996-8.