The Cardiac Arrhythmia Suppression Trial

To the Editor: Some proarrhythmia must be expected with the use of all antiarrhythmic drugs. The results of any antiarrhythmic drug trial should therefore be considered in terms of an antiarrhythmia–proarrhythmia equilibrium, with beneficial outcome being an expression of the extent to which antiarrhythmic efficacy exceeds deaths from proarrhythmia. The risk inherent to the study population, provided by mortality figures from the placebo groups, is a major factor in establishing the balance. The Multicenter PostInfarction Research Group study 1 and the Cardiac Arrhythmia Pilot Study 2 provided meticulous preparation for an interventional trial, but the outcome of the Cardiac Arrhythmia Suppression Trial . . .