A Wide QRS Complex Tachycardia with Variation of Ventriculoatrial Interval: What is the Mechanism?

Abstract

The differential diagnosis for wide complex tachycardia includes all causes of narrow complex tachycardia with bundle branch block, all causes of narrow complex tachycardia with antegrade pre-excitation, ventricular tachycardia, and antidromic and other pre-excited reciprocating tachycardias. The variation in a specific intracardiac interval that causes a subsequent change in the tachycardia cycle length or another intracardiac interval can be diagnostic in these arrhythmias.