New pacemaker cuts heart-failure deaths

Mortality rate lowered by half, hospitalizations by a third, study finds

February 12, 2003|By Jonathan Bor | Jonathan Bor,SUN STAFF

A new type of cardiac pacemaker greatly reduces deaths and hospitalizations caused by heart failure, a new study has found.

Pulling together four short-term studies, doctors at the Johns Hopkins School of Medicine found that the pacemakers can cut the death rate in half and reduce hospitalizations by nearly a third.

Previous studies showed that the pacemakers improve patients' strength and endurance, and thus their overall quality of life. "By analyzing the studies done to date, we found that the therapy also reduces mortality from heart failure," said David J. Bradley, principal investigator of the study, which appears in today's Journal of the American Medical Association.

The devices are designed for patients with moderate to severe heart failure whose left ventricle - the chamber that forces blood out of the heart - pumps in a sloppy, uncoordinated fashion. This group constitutes as much as 10 percent of the 5 million people who suffer from the condition.

Implanted in the left chest wall, the new devices are known as biventricular pacemakers because they stimulate both the right and left chambers. They were approved by the U.S. Food and Drug Administration in 2001 and have since become available at many large medical centers.

Heart failure occurs when the heart weakens and cannot pump enough blood to all regions of the body. It can result from heart attack, high blood pressure or heart valve disease.

The condition, which accounts for 1 million hospitalizations and 287,000 deaths each year, is becoming more common, in part because medical advances enable more people to survive heart attacks.

"We can often save heart attack patients with drugs like thrombolytics or with angioplasty, but they survive with weakened hearts, and often progress to heart failure or other troubles," said Dr. Neil R. Powe, director of the Johns Hopkins Welch Center for Prevention, Epidemiology and Clinical Research.

The Hopkins researchers pulled together four studies that, individually, were too small to produce statistically significant results. By considering them as a group, scientists were able to reach a more definitive conclusion.

The studies involved 1,634 patients who were already receiving medication for their heart failure. All of the patients subsequently received the new pacemakers - also known as cardiac resynchronization therapy devices - in addition to drug therapy, but only half had the pacemakers activated.

Researchers followed the patients' progress for three to six months. Another study that tracked 1,600 patients over a longer period is scheduled to be published later this year.

In another study, an international group of doctors found that concerns about side effects of beta blockers, a medication widely prescribed to treat heart failure, were unwarranted.

"Both [beta blockers] and cardiac resynchronization improve well-being and prolong life in patients with severe congestive heart failure," said Dr. Sergio L. Pinski, a Florida cardiologist, in a JAMA editorial.

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