Rare Cause of Wide QRS Tachycardia

Figure 3

Results of electrophysiological investigation: (a) sinus rhythm; His bundle electrogram shows normal AH interval (93 ms) and delayed conduction in His-Purkinje system (HV interval 74 ms); (b) Bundle branch reentrant ventricular tachycardia: VA dissociation points to localization of reentrant circle within ventricles; typical bundle branch reentrant tachycardia features are (1) His bundle potential (H) precedes QRS in every beat and (2) HV interval in LBBB-shaped tachycardia (86 ms) is longer than HV interval on sinus rhythm. Tachycardia uses RBB as anterograde limb and LBB as retrograde limb of reentrant circuit; HRA, high right atrium; RVA, right ventricle apex; HIS, His bundle electrogram.

(a)

(b)