Combination Pacemaker-Defibrillator Prevents Death from Heart Failure

St. Louis, Dec. 9, 2002 — A new implantable device has been found to reduce the risk of death from congestive heart failure by 40 percent, triggering the early halt of a national trial of the device.

“This trial was the largest one in history to test an implanted pacemaker or defibrillator, and it represents a landmark study for the treatment of congestive heart failure,” says Mitchell N. Faddis, M.D., Ph.D., assistant professor of medicine at Washington University School of Medicine in St. Louis. “I think this is one of the most important therapies developed in the last decade for treatment of severe heart disease.”

Faddis and Joseph G. Rogers, M.D., associate professor of medicine, led the participating team at Washington University. The School of Medicine, in collaboration with Barnes-Jewish Hospital, had one of the largest enrollments in the trial. The trial, called COMPANION (Comparison of Medical Therapy, Pacing and Defibrillation in Chronic Heart Failure), was sponsored by Guidant Co.

Roughly 5 million Americans suffer from congestive heart failure, in which the heart cannot sufficiently supply the body with blood. In about one-third of these individuals, the heart’s electric signal fails to reach the right and left lower chambers of the heart. As a result, the chambers do not contract at the same time. Blood therefore sloshes back and forth rather than being forced outward by a two-sided, synchronized effort.

Patients with this form of congestive heart failure do not benefit from traditional implantable pacemakers, which send electric signals only to the right side of the heart. Moreover, about half of all deaths from heart failure are sudden, which implies that an unexpected heart rhythm abnormality is to blame.

The COMPANION trial evaluated the ability of a two-component device to prevent life-threatening heart-rhythm abnormalities: A biventricular pacemaker, which supplies signals to both lower chambers and thereby re-coordinate contractions, and a defribrillator, which can jolt the heart back to life if it suddenly stops beating properly.

Researchers planned to recruit 2,100 people to enroll in the study at over 100 institutions around the country. However, after enrolling over 1,600 patients it became clear that the combination device was about 40 percent more effective in reducing mortality than traditional therapy, and the trial was terminated.

“This treatment has the potential to drastically improve the quality and duration of life for about 30 percent of all patients who are severely limited by weak hearts,” says Faddis. “It’s been particularly gratifying for me to participate in this trial because of the improvements most of my patients have experienced.”

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