Women's Heart Advisor July 2011 Issue

Sophisticated Device for Heart Failure Works Best in Women

Research indicates Cardiac synchronization therapy with defibrillation may actually reverse heart muscle damage caused by the condition.

If you are a woman in the early stages of heart failure, cardiac synchronization therapy with defibrillation (CRT-D) might be the most effective way to put pep in your step, stop your heart failure from progressing and prevent you from dying from a cardiac arrhythmia.

CRT-D combines an implantable cardioverter-defibrillator (ICD) with cardiac resynchronization. ICDs shock irregular heart rhythms back to normal, much like external shock paddles. Resynchonization therapy improves the heart’s pumping ability, which reduces and reverses many of the symptoms of heart failure.

A substudy of the Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy (MADIT-CRT), published in the February 7 issue of the Journal of the American College of Cardiology, looked at whether there was any different in outcomes between the male and female participants. Indeed, there was.

In women, CRT-D reduced the risk of death from arrhythmia or heart failure by 72 percent, compared with 28 percent for men. It also did a better job at boosting their heart function, reducing symptoms of heart failure. In women with QRS greater than or equal to 150 milliseconds—indicating a delay the signals synchronizing the heart’s pumping chambers—or with left bundle branch block, CRT-D was even more effective.

Even more encouraging was the finding that the women’s hearts showed evidence of reverse remodeling. In other words, CRT-D undid some of the damage caused by heart failure.

"The reason for this sex-related benefit is unclear. No prior study has demonstrated a significantly greater benefit from device therapy for women than men, regarding mortality or cardiac related outcomes in an overall study population or by disease etiology," say the study authors.