Defibrillator May Not Help Many With Heart Failure

Mar. 17 -- MONDAY, March 16 (HealthDay News) -- Implanted defibrillators don't seem to provide any particular benefit to many people with heart failure, a new study finds.

A defibrillator can provide a lifesaving electrical jolt when heart rhythm becomes abnormal enough to be fatal. But it generally does nothing for heart failure, the progressive loss of the heart's ability to pump blood nor does it help any life-threatening illness that might accompany heart failure, such as diabetes, cancer or kidney disease.

These illnesses, or comorbidities, are more common in elderly heart failure patients, said Dr. Soko Setoguchi, an instructor in medicine at Harvard Medical School and lead author of the study, published in the Canadian Medical Association Journal, on the benefits -- or lack of them -- of defibrillators in such cases.

There are guidelines on implanted defibrillators, based on the results of controlled trials, "but the guidelines do not say anything about which population of heart failure patients should get them," she said. "Most trials exclude older patients and patients with comorbidities, but heart failure patients usually are very old and have comorbidities."

To study what happens in real-life medical practice, Setoguchi and her colleagues analyzed data on 14,374 people hospitalized for heart failure, looking specifically at cardiac deaths that occurred outside of a hospital.

The potential benefit of an implanted defibrillator was assessed by assuming that all of those deaths -- involving 13.7 percent of the people in the study -- were caused by cardiac emergency situations that defibrillators are supposed to prevent.

That assumption gives defibrillators the benefit of the doubt because not all deaths are sudden and from cardiac causes. Yet the net potential benefit based on that assumption was an extra seven months. It dropped to about three months for those who had three hospitalizations for heart failure.

Survival time was extended by more than two years for heart failure patients who were younger than 65 and did not have kidney disease, cancer or dementia, the study found. But the average age of the people in the study was 77, and 21 percent had chronic kidney disease.