We present a 36 year-old male without overt cardiac disease who suffered, since he was 15 years-old, from sustained monomorphic ventricular tachycardia of left bundle branch block with a right axis, lasting for several hours; sometimes, syncope was a clinical form of manifestation. Electrophysiologic study, twenty-four hours Holter recording, cardiac catheterization and blood analysis were not useful in order to find its etiology. Efficacy of different drugs, like Mexiletil, Amiodarone, Atenolol and Verapamil (at a dose of 240 mg/day) were tested through multistaged graded-treadmill stress-testing using the Bruce protocol. Ventricular tachycardia was suppressed by administration of Lidocaine. Oral verapamil given at a dose of 360 mg/day prevented the induction of the arrhythmia, the efficacy was tested with maximal treadmill exercise and twenty-four hours Holter recording.