Results of the study, which analyzed clinical trials of pacemaker therapy for heart failure involving a total of 1,634 patients, are published in the Feb. 12 issue of The Journal of the American Medical Association.
"The devices range in cost from $20,000 to $50,000," says lead author David J. Bradley, M.D., Ph.D., a cardiology fellow. "These specialized pacemakers have been known to improve the quality of life for heart failure patients, but whether they also save lives had been unclear."
Heart failure accounts for more than 700,000 hospitalizations among Medicare beneficiaries every year, Bradley says. In the year 2000, hospitalization charges amounted to $14 billion. Half of deaths among these patients are caused by progressive cardiac dysfunction, which pacemakers help correct by stimulating the heart muscle to contract, pumping blood to the body.
Heart failure, which affects nearly 5 million people in the United States, is a condition in which the heart can't pump enough blood to the body's other organs. This can result from assorted problems including heart attack, high blood pressure or heart valve disease. The "failing" heart keeps working but not as efficiently as it should. People with heart failure can't exert themselves because they become short of breath and tired.
Advances in technology have increased the number of people diagnosed with heart failure each year, says senior author Neil R. Powe, M.D., M.P.H., director of Johns Hopkins' Welch Center for Prevention, Epidemiology and Clinical Research. About 550,000 new patients are diagnosed annually, he says.
"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," says Powe, also a professor of medicine and epidemiology at Johns Hopkins.
Bradley, Powe and colleagues searched medical databases for randomized clinical trials comparing pacemaker therapy (called "cardiac resynchronization") versus no therapy in patients with dysfunction of the left ventricle, the heart's main pumping chamber. Four studies of 1,634 patients were selected for analysis. The majority of patients were men ages 63 to 66 with moderate to severe heart failure.
In the studies, patients were divided into two groups; some received cardiac resynchronization while others did not. In cardiac resynchronization, a pacemaker lead positioned in a coronary vein by the left ventricle enhances cardiac function, and improves exercise capacity and quality of life among patients. In the Johns Hopkins study, cardiac resynchronization reduced death from progressive heart failure by 51 percent. The death rate was 1.7 percent for those who got resynchronization and 3.5 percent for those who did not. The pacemaker therapy also reduced hospitalizations by 29 percent and showed a trend toward reducing death of any cause.
Bradley notes the death rates overall were low, as the trials only followed patients for three to six months.
Study co-authors were Elizabeth A. Bradley, M.D.; Kenneth L. Baughman, M.D.; Ronald D. Berger, M.D.; Hugh Calkins, M.D.; Steven N. Goodman, M.D., Ph.D.; and David A. Kass, M.D. Baughman is currently at Brigham and Women's Hospital in Boston. Bradley, D.J. et al, "Cardiac Resynchronization and Death From Progressive Heart Failure: A Meta-analysis of Randomized Controlled Trials," The Journal of the American Medical Association, Feb. 12, 2003, Vol. 289, pages 730-740.
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