A 50 year old woman was admitted to our department to undergo an assessment of recurrent wide QRS tachycardia. An electrophysiologic study was performed. Ventricular tachycardia (VT) of three different morphologies, with left and right bundle branch block configurations, were induced with double extrastimuli from the right ventricle (left panel), thus suggesting that arrhythmogenic substrates existed in both the right and left ventricles. Endocardial mapping study showed that the site of earliest …