- Atrial esophageal fistula. The hallmark of this complication is onset of a plethora of what Dr. Asirvatham called “funny symptoms” more than a month post ablation. These include fever, transient ischemic attacks (TIAs), sepsislike symptoms, discomfort in swallowing, and in some cases hemoptysis.
“The predominant picture is endocarditis/TIA/stroke. If you see this, and the patient has had ablation, immediately refer to surgery to have the fistula between the esophagus and heart fixed. This is not a patient where you say, ‘Nothing by mouth, give some antibiotics, and see what happens.’ I can tell you what will happen: The patient will die,” the cardiologist said.
- Atrial stiffness. This typically occurs about a month after a second or third ablation procedure, when the patient develops shortness of breath that keeps worsening.
“You think ‘pulmonary vein stenosis,’ but the CT scan shows the veins are wide open. Many of these patients will get misdiagnosed as having heart failure with preserved ejection fraction even though they never had it before. The problem here is the atrium has become too stiff from the ablation, and this stiff atrium causes increased pressure, resulting in the shortness of breath. Sometimes patients feel better over time, but sometimes it’s very difficult to treat. But it’s important to recognize atrial stiffness and exclude other causes like pulmonary vein stenosis,” Dr. Asirvatham continued.
- Gastroparesis. This occurs because of injury to the vagus nerve branches located at the top of the esophagus, with resultant delayed gastric emptying.
“It’s an uncomfortable feeling of fullness all the time. The patient will say, ‘It seems like I just ate, even though I ate 8 hours ago,” the electrophysiologist said. “Most of these patients will recover in about 6 months. They may feel better on a gastric motility agent, like a macrolide antibiotic. I personally have not seen a patient who did not feel better within 6-8 months.”
Novel treatment approaches: “A-fib may be an autonomic epilepsy of the heart”
“Patients sometimes will ask you, ‘What is this ablation? What does that mean?’ You have to be truthful and tell them that it’s just a fancy word for burning,” the electrophysiologist said.
Achievement of AF ablation without radiofrequency or cryoablation, instead utilizing nonthermal direct-current pulsed electrical fields, is “the hottest topic in the field of electrophysiology,” according to Dr. Asirvatham.
These electrical fields result in irreversible electroporation of targeted myocardial cell membranes, leading to cell death. It is a tissue-specific intervention, so it’s much less likely than conventional ablation to cause collateral damage to the esophagus and other structures.
“Direct current electroporation has transitioned from proof-of-concept studies to three relatively large patient trials. This is potentially an important breakthrough because if we don’t heat, a lot of the complications of A-fib ablation will probably decrease,” he explained.
Two other promising outside-the-box approaches to the treatment of AF are autonomic nervous system modulation at sites distant from the heart and particle beam ablation without need for cardiac catheters.
“If you put electrodes everywhere in the body to see where A-fib starts, it’s not in the atrium, not in the pulmonary veins, it’s in the nerves behind the pulmonary veins, and before those nerves it’s in some other area of the autonomic nervous system. This has given rise to the notion that A-fib may be an autonomic epilepsy of the heart,” according to the electrophysiologist.
This concept has given rise to a completely different approach to treatment of AF through neurostimulation. That’s how acupuncture works. Also, headphones have been used successfully to terminate and prevent AF by stimulating autonomic nerve centers near the ears. Low-level electrical stimulation of the vagus nerve in order to reduce stellate ganglion activity is under study. So is the application of botulinum toxin at key points in the autonomic nervous system.
“Catheters, drugs, and devices that target these areas, maybe without any ablation in the heart itself, is an exciting area of future management of A-fib,” he said.
Another promising approach is borrowed from radiation oncology: particulate ablation using beams of carbon atoms, protons, or photons.
“The first patients have now been treated for ventricular tachycardia and A-fib. It really is quite amazing how precise the lesion formation is. And with no catheters in the heart, clot can’t form on catheters,” he observed.
Dr. Asirvatham reported having no financial conflicts regarding his presentation, although he serves as a consultant to a handful of medical startup companies and holds patents on intellectual property, the royalties for which go directly to the Mayo Clinic.