Chances are you've never heard of electrophysiology, but it's a medical subspecialty you should know about if you are one of the 100,000 or so Americans who will have a heart defibrillator implanted this year.


An implantable cardioverter defibrillator monitors the heart's rhythm and delivers a shock if needed to keep an aberrant heart beating regularly. And the incidence of in-hospital complications is significantly lower when the implant is done by an electrophysiologist rather than an ordinary cardiologist, a thoracic surgeon or another specialist, according to a study published in the Journal of the American Medical Association.

"Electrophysiology is a subspecialty within cardiology," explained study author Jeptha P. Curtis, MD, an assistant professor of medicine at the Yale University School of Medicine's section of cardiovascular medicine. "You have to undergo two years of advanced training on the electrical activity of the heart to be eligible for board certification."

The Study

The study of a registry of 111,293 defibrillator implants, done between January 2006 and June 2007, found that 70.9% of them were performed by electrophysiologists, 21.9% were performed by other cardiologists. 1.7% by thoracic surgeons and 55% by other specialists.

When an electrophysiologist did the procedure, complications occurred in 35% of cases. The incidence was 4% for other cardiologists, and 5.8% for thoracic surgeons, according to the study.


"Our study suggests that, in general, people are better served by having them (defibrillators) implanted by electrophysiologists," Dr. Curtis said.

Specialized Defibrillator

Another marked difference found in the study concerned people who require an implanted defibrillator that provides cardiac resynchronization therapy (CRT-D). "These are patients with heart failure, in which the heart is not only weak and inefficient but also beats in a disorganized way," Dr. Curtis explained.

While a standard implanted defibrillator has one or two "leads---electrical wires attached to deliver impulses to the heart muscle-a CRT-D device uses three leads to keep the heart beating properly. Nearly one-third of the people in the study met criteria for a CRT-D implant, and the likelihood that they would get one was significantly higher when the procedure was done by an electrophysiologist, the study said.

CRT-D devices were implanted by electrophysiologists in 83.1% of such cases, compared to 75.8% when the implants were done by other cardiologists, 57.8% by thoracic surgeons and 74.8% by other specialists.


So a physician's training in electrophysiology can rightly be a matter of concern for someone getting a defibrillator, Dr. Curtis said. "I think it is reasonable for a patient to ask a doctor what his qualifications are," he said. "It would be very reasonable for patients to ask implanting physicians what are their results, what are the numbers."

Such information should be available at most large medical centers, and having that information available should be part of normal quality assurance," Dr. Curtis said.

Stephen C. Hammill, MD, is a member of the study group, a professor of medicine at the Mayo Clinic, a past president of the Heart Rhythm Society, and a qualified electrophysiologist. He said the study shows that "across the board as a group, electrophysiologists have a better outcome than cardiologists or thoracic surgeons."

"But it does not show what individual physicians' outcomes are," Dr. Hammill added. His recommendation is that anyone considering a defibrillator implant "needs to speak with his or her physician and be sure that the physician is comfortable with the level of expertise and training of the individual who will do the implant."

Follow-Up Study Needed

Further study is needed to see whether the benefits of having an implant done by an electrophysiologist continue after hospital discharge, Drs, Curtis and Hammill said. "We need a follow-up study to see what happens over time," said Dr. Curtis.

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