[Idiopathic left fascicular ventricular tachycardia: the evidence for a "bystander" bundle of His participation].

: Idiopathic left ventricular tachycardia is a rare arrhythmia whose electrophysiological basis is not yet well-defined. We report a case of idiopathic left ventricular tachycardia caused by a reentrant circuit limited exclusively to the two fascicles of the left bundle branch.