Figure legend
Figure 1. Wide QRS complex tachycardia with predominantly right bundle branch block (RBBB) morphology, but with some beats with left bundle branch block (LBBB) pattern, and some being blocked to the ventricles.
Figure 2. Last atrial paced beat inducing tachycardia (A). Wide complex tachycardia (B).
Figure 3. Atrioventricular nodal reentrant tachycardia (AVNRT) with cycle length variation based on H-H interval change. The H-A interval is fixed (linking H-A), but A-H interval varies because antegrade conduction is moving between more than one slow pathway and this determines the A-A interval variation.