Availability of defibrillators, implants boost odds of surviving fibrillation

Surviving ventricular fibrillation — a deadly, chaotic misfiring in the heart's lower chambers — depends on luck and, often, a well-placed public defibrillator. Without an immediate shock to the heart, death can come in minutes.

Ventricular fibrillation and other arrhythmias are the topic of today's Deseret Morning News/Intermountain Healthcare Hotline. From 10 a.m. to noon, cardiovascular surgeon John R. Doty and cardiologist Peter Weiss, both of Intermountain Medical Center's Utah Heart Clinic, will answer phoned-in questions.

In the days before public access defibrillators, surviving ventricular fibrillation depended on the luck of having someone nearby to do cardiopulmonary resuscitation and an emergency medical response team that arrived in time, so survival rates were low.

These days, the small defibrillator boxes hang on the walls of shopping malls, gyms and airports. The best place to go into ventricular fibrillation, jokes Weiss, is in a casino: In addition to defibrillators, there are cameras and people everywhere, "and they want to keep you alive, of course, so they can get your money."

Patients who survive are usually given an implantable defibrillator, which increases their chance of surviving another fibrillation episode to 98 percent, Weiss says. The implantable device shocks the heart from the inside.

Heart disease is the leading cause of ventricular arrhythmias, and a history of heart attack also increases the risk. So people deemed at a high risk of suffering cardiac arrest may also be implanted with a defibrillator.

The trick is identifying which patients are good candidates. Currently one measure is "ejection fraction," the percentage of blood the heart is able to pump out with each heartbeat. A normal percentage is 55 to 65 percent; anyone with an ejection fraction below 35 percent is considered a good candidate to have a defibrillator implanted.

"It's an accepted practice at this point," says Weiss, and is paid for by Medicare.

Another type of ventricular arrythmia, ventricular tachycardia, is an abnormal, rapid beating in the lower chambers than can lead to lethal ventricular fibrillation.

Patients who experience any kind of abnormal heart rhythms should let their doctors know, say Weiss and Doty. People can also contact Intermountain Medical Center's CARE (Cardiac Arrhythmia Evaluation) program at 507-3513.