Primary Prevention of Sudden Cardiac Death in Idiopathic Dilated Cardiomyopathy: The Cardiomyopathy Trial (CAT)

Background—Patients with idiopathic dilated cardiomyopathy (DCM) and impaired left ventricular ejection fraction have an increased risk of dying suddenly. Methods and Results—Patients with recent onset of DCM (≤9 months) and an ejection fraction ≤30% were randomly assigned to the implantation of an implantable cardioverter-defibrillator (ICD) or control. The primary end point of the trial was all-cause mortality at 1 year of follow-up. The trial was terminated after the inclusion of 104 patients because the all-cause mortality rate at 1 year did not reach the expected 30% in the control group. In August 2000, the vital status of all patients was updated by contacting patients, relatives, or local registration offices. One hundred four patients were enrolled in the trial: Fifty were assigned to ICD therapy and 54 to the control group. Mean follow-up was 22.8±4.3 months, on the basis of investigators’ follow-up. After 1 year, 6 patients were dead (4 in the ICD group and 2 in the control group). No sudden death occurred during the first and second years of follow-up. In August 2000, after a mean follow-up of 5.5±2.2 years, 30 deaths had occurred (13 in the ICD group and 17 in the control group). Cumulative survival was not significantly different between the two groups (93% and 80% in the control group versus 92% and 86% in the ICD group after 2 and 4 years, respectively). Conclusions—This trial did not provide evidence in favor of prophylactic ICD implantation in patients with DCM of recent onset and impaired left ventricular ejection fraction.