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Defibrillators Lower Heart Failure Death Rate

Medicare Poised to Expand Coverage of Implantable Defibrillators to 500,000 People

From the WebMD Archives

Jan. 19, 2005 -- Patients with mild to moderate heart failure survive longer with an implantable defibrillatorimplantable defibrillator than by taking a common drug for irregular heartbeats.

The research that confirms the effectiveness of implantable defibrillators over the drug amiodarone for preventing sudden cardiac death is prompting federal officials to expand coverage for the devices to more than half a million at-risk patients.

That is two to three times the number of Medicare beneficiaries who are currently eligible for the implantable cardioverter-defibrillators (ICDs), FDA Commissioner Mark B. McClellan, MD, PhD, announced Wednesday.

In a statement published along with the study, McClellan notes that most patients with serious heart failure would qualify for the devices.

"We expect to finalize this decision within days, after synthesizing public comments and the final published evidence," McClellan writes.

Too Few Patients Get ICDs

Sudden cardiac death remains a leading cause of death among people who have had heart attacks and/or have heart failure.

In heart failure, the heart can no longer pump enough blood to meet the body's needs. Patients with the condition can die suddenly from arrhythmias -- irregular heartbeats. Treatment options to prevent these life-threatening events include medications such as amiodarone and implantable defibrillators.

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The ICD is programmed to detect irregular heartbeats and give an electric shock when needed to reestablish normal rhythms.

Vice President Dick Cheney, who has a history of heart disease, became the world's most famous ICD recipient when he had the device implanted almost four years ago. But despite growing evidence of the lifesaving benefits of implantable defibrillators, only about 20% to 25% of patients who could potentially benefit from the devices are getting them, experts say.

A widely publicized study reported two years ago established the usefulness of ICDs among patients who had survived heart attacks. The risk of sudden death was reduced by 31% among survivors who got the devices compared with those who did not.

In the newly reported trial, published in the Jan. 20 issue of The New England Journal of Medicine, researchers evaluated the effectiveness of the ICD in patients with heart failure. Roughly 2,500 patients were enrolled in the trial.

Patients treated with conventional drug therapy for heart failure who also got an ICD were 23% less likely to die of sudden cardiac arrest than patients treated with conventional therapy plus amiodarone. The researchers concluded that the anti-arrhythmia drug did not improve long-term survival while the defibrillator did.

Know Your Ejection Fraction

All the patients in the trial had poorly functioning hearts, accessed by a simple test known as ejection fraction. Ejection fraction measures the heart's blood pumping efficiency.

A healthy heart pumps out 55% or more blood with each beat, but an ejection fraction below this number indicates that the heart is weakening. The patients in the study had ejection fractions of 35% or less.

McClellan notes that most heart patients with ejection fractions of 35% or less who are Medicare beneficiaries should soon qualify for ICDs. The devices cost about $30,000 per patient.

"If you have been told you have heart disease, you need to know your ejection fraction and talk to your doctor about it," Alan Kadish, MD, tells WebMD. Kadish and colleagues at Chicago's Northwestern Cardiovascular Institute conducted a similar trial of patients with heart failure treated with ICDs. He also reported a significant survival advantage among patients who got the devices.

"This test should be routine for heart patients, and, unfortunately, it is not," says Kadish. "Every patient who has had a heart attack and every patient with heart failure should have it."

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American Heart Association spokesman Dan Roden, MD, tells WebMD he expects the clinical impact of the new findings will be "huge."

"I think people have been waiting for confirmatory data showing the benefits of ICDs, and that is what this study provides," he says. But he adds that many patients who will now be candidates for the device probably don't need it and more study is needed to better define who will and will not benefit.

Studies have suggested that only about one in five patients who get ICDs end up having an arrhythmia that requires the device to send an electrical charge to the heart. Medicare is proposing a nationwide registry of its ICD recipients to help find out which patients will benefit most from them.

"Many people who end up getting these devices may not need them, but we have no way of knowing who they are right now," says Roden, who is a professor of medicine at Vanderbilt University Medical Center in Nashville, Tenn.

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Sources

SOURCES: Bardy et al. The New England Journal of Medicine, Jan. 20, 2005; vol 352: pp 225-237. McClellan, M. and Tunis, R. The New England Journal of Medicine, Jan. 20, 2005; vol 352: pp 222-224. Alan Kadish, MD, associate chief of cardiology, Northwestern Memorial Hospital; associate director, Northwestern Cardiovascular Institute, Chicago. Dan Roden, MD, professor of medicine and pharmacology, Vanderbilt University School of Medicine, Nashville, Tenn.
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