Figure 3 Phenomena observed during diagnostic process of patient
3
3A: Tachycardia switched between LBBB, RBBB and normal QRS morphology,
accompanied by cycle length change. 3B: Antegrade conduction of His
bundle during tachycardia. 3C: A His bundle refractory period
ventricular stimulus reset the tachycardia and antegrade conduction of
His bundle during ventricular pacing revealed the existence of accessory
pathway. 3D: Progressive QRS fusion and perfect PPI during RVA
entrainment. LBBB=left bundle branch block; RBBB=right bundle branch
block; PPI=post pacing interval.