Simulated 2:1 Left Bundle-Branch Block

Abstract

An arrhythmia is described in which ventricular extrasystoles occur in bigeminal rhythm during left bundle branch block. The ventricular extrasystoles originate in the left ventricle and occur late in diastole. This results in simultaneous activation of the ventricles by the supraventricular and ectopic ventricular impulses with consequent fusion complexes that normalize the bundle branch block pattern. 2:1 left bundle branch block is thus simulated.