Implantable Defibrillators May Not Help Women With Heart Failure

Sept. 15 -- MONDAY, Sept. 14 (HealthDay News) -- Widely used implantable cardioverter-defibrillators may not actually help women with advanced heart failure.

A new analysis turns up no evidence that the devices, used to detect and then correct abnormal heart rhythms, actually lowered the risk of death among female patients, despite the fact that this is routine therapy for all patients with heart failure.

"We do not know of the benefits of defibrillators when used as primary prevention," said Dr. Christian Machado, senior author of a paper appearing in the Sept. 14 issue of the Archives of Internal Medicine. "We just do not know how much women benefit from this therapy."

Yet, according to an accompanying editorial, 30 percent of people getting implantable cardioverter-defibrillators, also called ICDs, are women.

In fact, there are even guidelines supporting the practice, said Machado, who is director of electrophysiology at Providence Hospital Heart Institute, in Southfield, Mich.

ICDs are intended to prevent sudden cardiac death in heart failure patients, who have a high risk for such an event. And while clinical trials do support the practice, those trials tend to be biased towards men.

Here, a search of medical literature databases turned up only five relevant randomized clinical trials between 1950 and 2008. The trials involved a total of 934 women and 3,810 men, a clear indication that women are underrepresented in this type of study even though women make up almost half of the 5.3 million Americans who have heart failure.

None of the studies on their own showed any survival advantage for women of having a defibrillator implanted, nor did the combined data show any benefit.

But there was a reduction in death rates for men in each trial, as well as when the results were pooled together.

"We need to find a way to study more women in order to be able to identify what subgroups truly benefit from this therapy," Machado said.