Clinical aspects of trial design: what can we expect from the cardiac arrhythmia suppression trial?

The controlled clinical trial, i.e., a prospective study that compares the effect of one or more interventions against a control in human subjects, is the most definitive method to determine the benefit/risk ratio for a treatment. Some of the elements are a clear statement of the primary and secondary hypothesis, carefully defined end points, randomization, double blinding, and concomitant controls for the experimental treatment using either placebo or standard treatment. Randomization tends to produce study groups that are comparable with respect to both known and unknown factors that influence the outcome, and also removes bias in the assignment of subjects to treatments to ensure that statistical hypothesis testing will have valid significance levels. An adequate sample size is critically important for a successful trial. The Cardiac Arrhythmia Suppression Trial (CAST) is a randomized, placebo-controlled, double-blind, international, multicenter clinical trial to determine whether suppression of ventricular arrhythmias after myocardial infarction with long-term antiarrhythmic drug treatment will reduce arrhythmic death. Survivors of myocardial infarction who are less than 80 years of age and have greater than or equal to six ventricular premature depolarizations (VPD) per hour on a 24-hour continuous ECG recording obtained between 6 days and 2 years after myocardial infarction are eligible for CAST.(ABSTRACT TRUNCATED AT 250 WORDS)