Figure 1 Phenomena observed during diagnostic process of patient 1
1A: 4 rhythms and the corresponding A-H-V relationships. 1B: His bundle refractory period ventricular stimuli during tachycardia either reset or terminated tachycardia. 1C: RVA pacing dissociated V and H and fluoroscopy showed the successful ablation target at the triangle of Koch. 1D: Sketch map of the mechanism in different situations. RVA=right ventricular apex.