Fig. 1.

A. ECG in Wide Complex Tachycardia. Panel A illustrates his wide complex tachycardia at a rate of around 220 beats per minute. Positive inferior leads (II, III, aVF) indicate a basal/mid ventricular or outflow tract origin, and positive concordance throughout the precordial leads suggests a posterior ventricular origin and argues against a supraventricular tachycardia with aberrancy. B. Baseline ECG. Panel B illustrates his baseline ECG, which demonstrates nonspecific T wave flattening, a normal axis and notable lack of delta waves indicative of pre-excitation