Electrophysiologic evaluation of antiarrhythmic drugs.

Electrophysiologic techniques are used to assess the properties of antiarrhythmic drugs and also to provide support for the selection of antiarrhythmic therapy for individual patients. Assessment of the antiarrhythmic efficacy of drugs requires that the arrhythmia can be induced by programmed electrical stimulation and is critically dependent on the stimulation protocol. Continued inducibility on drug therapy appears to be a strong predictor of recurrences and sudden death, although the predictive value of electrophysiologic testing remains controversial for some drugs. These techniques may also be useful for determining the proarrhythmic potential of antiarrhythmic agents, but the aggravation of tachycardia that occurs in 10-30% of patients during electrophysiologic testing is unpredictable and its significance is unknown. The electrophysiologic approach to drug therapy has limitations, but, nevertheless, it is useful and should maintain a prominent place in the evaluation of antiarrhythmic therapy.