TUESDAY, Jan. 10, 2006 (HealthDay News) -- Implantable defibrillators save lives by shocking hearts back into a healthy rhythm, but that shock can also cause physical and psychological trauma for the patient.
However, a new Canadian study shows that drugs that help prevent abnormal heartbeats can reduce the need for defibrillator shocks, according to a report in the Jan. 11 issue of the Journal of the American Medical Association.
"There can be a fair amount of psychological trauma from the shock, and it is actually fairly painful," noted Dr. Jeffrey J. Goldberger, director of cardiac electrophysiology at Northwestern University. He was not involved in the study, but has long worked with patients equipped with implanted defibrillators.
The new international study was led by Dr. Stuart Connolly of McMaster University, in Hamilton, Ontario, and included 412 heart patients who received implantable defibrillators at 39 medical centers in the United States, Canada and Europe. Some were given beta blockers, which are standard treatment in such cases. Others got beta blockers plus amiodarone, a drug that reduces abnormal heartbeats, while a third group received sotalol, another anti-arrhythmia drug.
The risk of a shock over one year was 56 percent lower in those who got either the amiodarone-beta blocker or sotalol treatment, compared to those who got beta blockers alone, the research team found. The amiodarone-beta blocker combination was the most effective, reducing incidence of shock by 73 percent.
There was a price to be paid in terms of side effects for those taking amiodarone, however. Some patients taking the drug reported abnormally slow heartbeats and lung and thyroid problems, the researchers noted.
"Should amiodarone or sotalol be immediately used after defibrillator implantation, or some time before a first shock occurs?" they asked. Their answer, based on the findings: "Therapeutic decisions should be individualized."
Goldberger agreed. In his practice, he said, "We typically individualize each patient, and we do not routinely put patients on amiodarone."
Dr. Robert L. Page is head of cardiology at the University of Washington and author of an accompanying editorial on the study. He agreed with Goldberger that treatment needs to be tailored to each patient.
Decisions on drug therapy might be made before implanting the defibrillator, based on the frequency of episodes of abnormal heartbeats or "anxiety or intolerance of shock in the past," Page said.
But for most patients, the decision would be made after implantation, "if there is an indication that something further is needed," he said. And while amiodarone is more effective, Page said, he might consider sotalol for some patients because it has a lower incidence of side effects.
Goldberger said he considers treatment with anti-arrhythmia drugs "when there is a high probability of a patient having events, a lot of arrhythmias, or if they already have had events." About 40 percent of his defibrillator patients get one of these drugs, he said. Page estimated that over 50 percent of his patients will take an anti-arrhythmia drug within two years after implantation, with most getting amiodarone.
"Ideally, it would be great if we could prevent all [shocks]," Goldberger said. "A defibrillator is a wonderful thing, it saves lives. But the mechanism by which it saves lives is [that] first you must have a cardiac arrest, then the defibrillator resuscitates. A more ideal way would be to prevent the arrest from happening."
More information
For more on implantable defibrillators, head to the American Heart Association.
