Proarrhythmic responses during electrophysiologic testing.

Proarrhythmia is a potentially lethal adverse effect of antiarrhythmic drugs. Underlying mechanisms and the approaches to identification are discussed. The applicability of electrophysiologic testing is considered, with particular reference to the validity of the different responses to programmed stimulation considered to be manifestations of proarrhythmia. The incidence of proarrhythmia in relation to individual antiarrhythmic agents is also reviewed.