Repetitive monomorphic ventricular tachycardia of left coronary cusp origin.

Repetitive monomorphic ventricular tachycardia with a morphology of inferior axis and left bundle branch block pattern in patients without structural heart disease commonly originates from the right ventricular outflow tract. We report the case of a 22-year-old man with an incessant, monomorphic ventricular tachycardia with a similar morphology originating from the left coronary cusp, which was confirmed by perfect pace mapping, local ventricular activation preceding the onset of QRS by 25 mse, and eliminated by a single delivery of low-energy (11 W) radiofrequency currents.