“Prophylactic implantation of a defibrillator in addition to medications should be considered as a recommended therapy in this patient population,” said Arthur J. Moss, MD, from the University of Rochester Medical Center, in front of a packed house in Hall D.

The four-year trial included 1,232 patients from 76 centers in the United States and Europe. Patients with a prior MI and a left ventricular ejection fraction of 0.30 or less were randomly assigned in a 3:2 ratio to receive an ICD (742 patients) or conventional medical therapy (490 patients), with all-cause mortality as the primary end point. Electrophysiologic testing or inducible ventricular arrhythmias were not eligibility criteria for MADIT II.

During 20 months of follow up of the study group, there was a 31 percent reduction in the relative risk of mortality among patients in the ICD group as compared those in the conventional therapy group, Dr. Moss reported.

Because of the reduced risk of mortality seen in the trial, the Data Safety and Monitoring Board stopped the trial early (November 2001). The results are especially significant, Dr. Moss said at a news conference later in the day, because ICD therapy was “on top of optimal medical management.” Use of beta blockers in both treatment arms, for example, was 70 percent, and use of statins was 67 percent in the ICD group and 64 percent in the conventional therapy group.

ICD therapy was associated with the expected rates of device-related complications, Dr. Moss said, but, more importantly, was also associated with a higher rate of new or worsened heart failure than was conventional therapy. While this was a troublesome finding, he said, the research team speculated that effective treatment of potential lethal arrhythmias leads to longer survival, thus allowing heart failure to develop.

Economic implications loom

The potential patient population that could benefit from prophylactic treatment is large—an estimated three to four million patients have coronary artery disease and advanced left ventricular dysfunction in the United States, with an estimated 400,000 new cases annually.

“If a meaningful number of these patients receive an ICD prophylactically, the cost to the health care system would be substantial,” Dr. Moss said. But “market forces,” he argued, would eventually drive down the cost of this therapy.

Repeating a warning from an editorial he wrote in Circulation last year, ACC Immediate Past President Douglas P. Zipes, MD, who moderated the news conference, said that, at their current cost, expanded use of ICDs “could have profound implications for the health care budget.”

To reduce the potential economic impact, Dr. Zipes reiterated his call for device companies to consider making two different classes of ICDs: a cheaper, stripped down version with limited capabilities for lower-risk patients, and the more sophisticated devices currently being manufactured.