Predicting antiarrhythmic performance

Antiarrhythmic therapy in the past was guided by observational studies. However, optimum patient care now demands evidence derived from large clinical trials. Unfortunately, because large-scale mortality trials are expensive and time consuming, surrogate markers were used in many clinical studies. However, the use of surrogate markers for antiarrhythmic drug efficacy was called into question after the publication of studies such as the Cardiac Arrhythmia Suppression Trial (CAST) and the Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) trial. Currently, in order to predict antiarrhythmic performance, clinicians must rely on mortality trials for guidance in treating atrial and ventricular arrhythmias. Although the practicing physician has a large number of studies to draw from, the study design and patient population are critical variables that must be understood before trial results can be applied to patient care. This review focuses on the results of the major clinical antiarrhythmic drug trials published in the last 10 years. Patient variables (e.g., the presence or absence of structural heart disease) and problems in study design that may have affected outcome are emphasized as an aid to interpreting results of current and future clinical trials.