Idiopathic ventricular tachycardia originating in the great cardiac vein

A 44-year-old woman with no structural heart disease and a history of recurrent wide complex tachycardia was referred for radiofrequency (RF) ablation of idiopathic ventricular tachycardia (VT). Electrophysiologic study demonstrated normal sinus rhythm with frequent premature ventricular beats, a left bundle branch block morphology, and inferior axis identical to the previously documented tachycardia. Sustained VT of the same morphology was easily induced with ventricular burst pacing during isoproterenol infusion at 2 μg/min (Figure 1A).