Women with implantable cardioverter defibrillators fare less well than men

While ICDs - implantable cardioverter defibrillators - are the device of choice to manage abnormal heart rhythms, a new study led by cardiologists at the University of Pennsylvania School of Medicine suggests that women with ICDs fare less well than their male counterparts.

In a retrospective analysis to be presented at the AHA Scientific Sessions 2007 on Sunday, November 4 (Poster #C148; 3 p.m.), lead researcher Andrea Russo, M.D., Clinical Associate Professor of Medicine, suggests that despite the proven overall effectiveness of the devices, women had a greater risk of dying than men.

Using data from the completed INTRINSIC RV trial, the researchers compared results from 1237 men and 293 women. (The INTRINSIC RV trial, which was completed in 2006, compared dual- and single-chamber ICDs.)

“There is a paucity of data comparing outcome and arrhythmic events in men vs. women with ICDs,” said Dr. Russo, who is also Director of the Electrophysiology Laboratory at Penn Presbyterian Medical Center. “We chose the INTRINSIC RV study because it enrolled the largest total number of women.”

The researchers found that women with ICDs required hospitalization and had a higher mortality than men with the device. However, after adjusting for other factors, such as the presence of coronary artery disease, heart failure and medical treatment, these gender differences in outcome were no longer present.

According to Dr. Russo, this means that women may be sicker by the time they receive ICDs. In addition, women appear to be under-treated with medications such as beta-blockers and ACE inhibitors in this study. On the other hand, she notes, women appeared to be just as likely as men to receive appropriate shocks from their devices for abnormal rapid rhythms from the lower chamber of the heart.

“This research confirms the need for additional studies to learn why there is such a disparity between the sexes,” Dr. Russo says. “Then we also can learn which women will most benefit from the devices.”

In conclusion, the researchers postulate that the differences may be related to how aging and lifestyle factors affect women and men who receive ICDs. They recommend that additional research focus on gender differences among patients who receive implantable cardioverter defibrillators.