Broad complex tachycardia; never judge a?book by its cover

摘要

The electrocardiogram (ECG) at admission showed a broad complex tachycardia of 138 bpm with superior axis, left bundle branch block (LBBB) morphology and a transition in lead V5. There was no apparent atrioventricular (AV) dissociation. His device for cardiac resynchronisation therapy with defibrillator function (CRT-D) was interrogated and showed a regular tachycardia with 1:1 AV relationship and a short ventriculoatrial (VA) time (60ms, not compatible with a concealed bypass) (Fig. 1a).