U. ROCHESTER (US)—Results from the largest clinical trial of its kind could change the way doctors treat cardiac patients. Heart failure risk drops by more than 40 percent when doctors couple an implanted cardiac defibrillator (ICD) with an additional implant that resynchronizes the heartbeat.

The results were even more dramatic for women, with a 63 percent reduction in heart failure risk.

The implant, known as cardiac resynchronization therapy (CRT), is currently approved for treatment only for patients with symptoms of severe heart failure—identified by the New York Heart Association (NYHA) as class III or IV—to improve the heart’s mechanical pumping action.


A CRT-D device is implanted in the chest to prevent heart failure. “There is a very large population of patients with heart disease whom we believe will benefit from CRT-D therapy,” says Arthur Moss.

The new trial sought to determine if preventive CRT-D therapy, the combination of an ICD with CRT, could reduce the risk of mortality and heart failure in patients with mild cardiac disease and few symptoms.

“This is a very important trial,” says Richard Page, president of the Heart Rhythm Society. “Previous studies have shown that the ICD saves lives. This trial demonstrates that in this population, an ICD with biventricular pacing can be expected also to improve clinical outcome as measured by hospitalization for heart failure. I anticipate that these results may improve acceptance of ICD therapy, both by patients and their physicians, in that the patient would not only live longer, but also would live better.”

The clinical trial enrolled 1,820 patients from 110 medical centers in the United States, Canada, and Europe for more than four years. Arthur Moss, professor of medicine at the University of Rochester, led the trial, which is the world’s largest randomized study involving patients with mild cardiac disease—NYHA class I or II. About 70 percent of the approximately 5.5 million Americans with some form of heart disease are considered class I or II.

About one million cardiac patients in the United States die each year from either electrical problems, heart rhythm disorders that result in sudden cardiac death, or from mechanical malfunctions where the heart’s pumping ability is impaired (heart failure), according to the study authors.

“There is a very large population of patients with heart disease whom we believe will benefit from CRT-D therapy,” says Moss.

In 2002, Moss and a research group known as MADIT (Multicenter Automatic Defibrillator Implantation Trial) showed that an ICD reduced the risk of death by 31 percent in cardiac patients. This therapy was soon approved by the U.S. Food and Drug Administration and became part of professional guidelines from the American Heart Association, the American College of Cardiology, and the Heart Rhythm Society.

Long-term follow-up studies showed, however, that ICDs were so effective at preventing sudden death that patients lived longer and were subsequently at increased risk for heart failure. This created an urgent need to better address both risks in tandem.

The trial was sponsored by Boston Scientific Corp. through a research grant to the University of Rochester. Findings were published in the Sept. 1 issue of the New England Journal of Medicine and presented at the European Society of Cardiology Congress in Barcelona, Spain

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