Fig. 1.

Electrocardiographic tracings identify site of origin of ventricular ectopy. (A) demonstrates ventricular ectopy from anterolateral papillary muscle with wide QRS complex and atypical right bundle branch block morphology (V1 lead) and inferior right axis. (B) presents posteromedial papillary muscle ventricular tachycardia with similar atypical right bundle branch block morphology but superior and left axis. (C) Right ventricular outflow tract ectopy with negative in V1 lead (left bundle branch bock morphology) and positive deflection in leads II, III, and aVF. In contrast to ectopy from left ventricular outflow tract, (D) which has positive reflection in V1 lead.