Fig. 3. MADIT trial results: Actuarial survival curves for patients treated wtih the defibrillator and with conventional therapy. (From: Moss AJ, Hall J, Cannom DS, Daubert JP, et al. Improved survival with an implanted defibrillator in patients with coronary artery disease at high risk for ventricular arrhythmia. N Engl J Med 1996;335:1933-1940. Copyright © 1996 Massachusetts Medical Society.)
substantial separation in favor of the defibrillator, which was maintained throughout the follow-up period, and was highly significant (p = 0.009).
The results of MADIT were sufficiently striking that in a highly unusual move, the Food and Drug Administration (FDA) was compelled to rapidly expand the indications for the ICD to include patients who met the MADIT entrance criteria.
The Coronary-Artery Bypass Graft (CABG) Patch Trial
CABG Patch (15) enrolled patients who were scheduled to have coronary-artery bypass grafting for ischemic heart disease, who had LVEFs of less than 0.36, and who had positive signal-averaged electrocardiograms (SAECGs). Randomization itself took place in the operating room, once the revascularization was completed and the patient was deemed stable. Patients deemed eligible at that point were randomized to either receive or not receive the ICD.
A total of 1055 patients were enrolled during the 4 years of the study, and were followed for a mean of 32 mo postoperatively. In April 1997, the study's Data Safety Monitoring Board terminated the trial when it was determined that no survival benefit was provided by the ICD in this population. In fact, the survival curves from both the defibrillator and control groups were virtually identical (Fig. 4). Subsequent analyses showed that the ICD reduced the risk of sudden cardiac death significantly, but the risk of arrhythmic death in this population was lower than expected, leaving the trial inadequate to detect a difference in total mortality (15a).
Multicenter Unsustained Tachycardia Trial (MUSTT)
MUSTT was not specifically designed to test whether the ICD can prolong overall survival when used as primary prophylaxis (16). Instead, it was designed to test the hypothesis that antiarrhythmic therapy guided by electrophysiologic testing can benefit patients with NSVT, left ventricular dysfunction, coronary-artery disease (CAD) and
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