Disabling Palpitations in an Adolescent

A teenage girl presented with recurrent episodes of palpitations for 6 consecutive years. The resting 12-lead electrocardiogram showed sinus rhythm with no preexcitation or repolarization abnormalities. Therewere incessantmultiple runsof nonsustainedventricular tachycardiawith right bundle branch block morphologic features.QRS complexeswere negative in the rest of theprecordial leads (V2-V6) and in leads I andavL, butpositive in III, avR, andavF, suggesting a left (lateral) ventricular apical origin (Figure 1). The echocardiogram showed no structural abnormalities. The patientwas prescribed sotalol but her symptomsdidnot improve. Invasive electrophysiological mapping of the left ventricle endocardium demonstrated that the ventricular tachycardia probably originated from the epicardial surface of left ventricular apex. Quiz at jamacardiology.com Figure 1. Twelve-lead surface electrocardiogram during tachycardia. QRS complexes are positive in V1, negative in the rest of the precordial leads (V2-V6), and negative in leads I and avL but positive in III, avR, and avF.