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November 2002
Volume XXVIII, Number 5
Revised guidelines crafted by cardiology experts outline important new uses for implantable cardioverter defibrillators (ICDs)--sophisticated devices which stimulate the heart to beat with a steady rhythm and deliver an electrical shock if the heart's rhythm becomes dangerously fast or erratic. ICDs have been proven to enhance the quality of life and to improve survival of patients recovering from a heart attack whose hearts have significantly impaired ability to pump.
"The type of therapy that we are talking about--called biventricular pacing--allows for resynchronization of the way the heart contracts and quite remarkably has significantly ameliorated symptoms of heart failure," explained Dr. Mark Schoenfeld, president of the North American Society of Pacing and Electrophysiology and clinical professor of medicine at Yale University. "In addition, it improves the patient's overall ejection fraction--the amount of blood that gets ejected with every heartbeat. And it has reduced the number of hospitalizations related to heart failure."
The new recommendations point out the need for patients to know as much about their hearts as possible, including whether they have a decreased ejection fraction. The ejection fraction in people with a healthy heart normally exceeds 50 percent. Studies show that an ICD can reduce the risk of death by nearly one-third in heart attack patients with an ejection fraction of 30 percent or less.
"I will go on record as saying that the ejection fraction may well be one of the most important things that general physicians should be checking," says Dr. Schoenfeld, who helped develop the guidelines in collaboration with the American College of Cardiology and the American Heart Association. "The ejection fraction should unequivocally be determined if someone has had heart problems--whether it be a past heart attack or something to suggest symptoms of heart failure. It may turn out to be as important in determining patient outcome as cholesterol is."
The guidelines, last revised in 1998, also expand the use of ICDs to patients whose hearts pump with too little force and are hindered by a sluggish electrical system--a common conduction disturbance called left bundle branch block, which accounts for about 25 percent of patients with heart failure.
Additional changes in the use of ICDs include recommendations for patients with an inherited risk of sudden death, or a history of fainting caused by arrhythmias or other heart problems. Some private insurers have begun accepting and paying for the expanded use of ICDs. The Centers for Medicare and Medicaid Services are expected to announce their coverage decision by year's end.
Full text of the 2002 guideline update for implantation of cardiac pacemakers and antiarrhythmia devices is posted at www.americanheart.org.
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