Researchers conclude that a special kind of heart pacemaker combined with a defibrillator significantly reduces the risk of death and hospitalization in certain patients with severe heart failure, compared to drug therapy alone. The results of the 128-center study, which included the University of Maryland Medical Center, are published in the May 20, 2004, issue of the New England Journal of Medicine.
“These are important results, and may have a major impact on the way cardiologists treat heart failure in patients whose pumping function has been severely limited,” says Stephen S. Gottlieb, M.D., cardiologist and an investigator for the study at the University of Maryland Medical Center.
“There is now good evidence that this therapy is beneficial for some people with heart failure,” adds Dr. Gottlieb, who is also a professor of medicine at the University of Maryland School of Medicine.
More than 1,500 patients took part in the study, known as the COMPANION (Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure) Trial. They all had abnormal electrocardiogram readings and a poorly functioning left ventricle, the heart’s main pumping chamber. They were randomly assigned to one of three groups.
Twenty percent of the patients were given medications alone. A second group (40 percent of patients) received medications plus an implantable bi-ventricular pacemaker. The device provides cardiac resynchronization therapy by delivering electrical stimulation to both sides of the heart. A third group (40 percent) received medications plus an implantable device, called a resynchronization pacemaker plus defibrillator, that not only synchronizes the heartbeat but also contains a defibrillator to shock the heart back to normal in case of a dangerously irregular heart rhythm.
The primary goal of the study was to compare the three groups in terms of death or hospitalization for any reason. Compared to medication alone, the final data indicate:
Dr. Gottlieb says the pacemaker, whether alone or combined with a defibrillator, probably played a role in reducing hospitalizations, because it can relieve the symptoms of heart failure, such as congestion in the lungs. “The patient feels better and therefore is less likely to require treatment in a hospital,” says Dr. Gottlieb.
Adding the defibrillator has a definite impact on survival, according to Dr. Gottlieb. “When death rates alone were investigated, the 36 percent reduction in risk indicated a major benefit in the group that received the combined pacemaker-defibrillator.”
Dr. Gottlieb cautions that these devices would be considered only for patients who meet certain criteria, and would affect about 15 percent of people with heart failure.
Heart failure, which can result from a severe heart attack, is a progressive disorder in which the heart loses its ability to pump blood effectively. About 5 million Americans are living with heart failure. Approximately 550,000 new cases are diagnosed each year and 51,500 die from it annually, according to the American Heart Association.
Stephen R. Shorofsky, M.D., Ph.D., associate professor of medicine at the University of Maryland School of Medicine and head of electrophysiology at the University of Maryland Medical Center was also an investigator in the study.
Guidant Corporation funded the COMPANION trial.
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