The Cardiac Arrhythmia Pilot Study. The CAPS investigators

Frequent or repetitive ventricular premature complexes (VPCs) occurring soon after acute myocardial infarction are predictors of subsequent mortality independent of left ventricular dysfunction. The Cardiac Arrhythmia Pilot Study (CAPS) is a 10-center study sponsored by the National Heart, Lung, and Blood Institute to determine whether postinfarction ventricular arrhythmias can be satisfactorily reduced for 1 year after acute myocardial infarction. Patients younger than 75 years are screened for arrhythmias 6 to 60 days after acute myocardial infarction. To qualify for CAPS, patients must have at least 10 VPCs or at least 5 runs of 3 to 9 consecutive VPCs in a 24-hour electrocardiographic recording and a left ventricular ejection fraction greater than 0.20. Eligible patients without exclusion criteria are randomized into 1 of 5 treatment tracks (4 active treatment and 1 placebo). Within a treatment track, patients are permitted to change drug and dosage in order to achieve at least 70% reduction in VPC frequency and at least 90% reduction in runs of VPCs over 1 year of follow-up. In addition to efficacy assessment, adverse effects, particularly proarrhythmic effects, are being monitored. The results in CAPS will be pivotal for deciding whether a fullscale trial to determine whether controlling ventricular arrhythmias will reduce mortality risk is feasible.