Experimental models of torsades de pointes

: Several experimental models of torsades de pointes have been proposed these last years. They can be classified in 2 categories: morphological models designed to reproduce the ECG features of "torsade", with in vivo ventricular stimulations or with computer ECG stimulations and pharmacological models designed to obtain in vivo early after depolarizations, with toxic agents such as cesium chloride and anthopleurine, or with commercialized or new pharmaceutical drugs. These models improved electrophysiologic and pharmacologic knowledge of torsades de pointes. The respective roles of early after depolarizations in torsades initiation and of reentry in the following beats of the salvos is now recognized. Induction protocols were described, which appeared to involve an inotropic potentiation following burst or repetitive extrastimuli. A more accurate evaluation of arrhythmogenic risk associated with new drugs could be developed.