Outcomes of Different Ablation Approaches for Para-Hisian Accessory Pathway and Ablation Safety at Each Site

Figures

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  Figure 1. (A), ABL was at site 1, which locates at a superior part above the real “His” with far-field “His” potential recorded; (B), Site 2 (true para-hisian): the site with near-field “His” potential; (C), Site 3: inferior part below site 2 with far-field “His” potential recorded; (D), RMS: the site bounded anteriorly by His recording location and posteriorly by the roof of CS ostium without “His” potential recorded; (E), left anterior oblique view of the tricuspid annulus and right anterior septum was divided into three subgroups. Real “His” was labeled with yellow dots and far-field “His” was marked with brown dots. ABL, ablation catheter; RMS, right midseptal.

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  Figure 2. (A), left panel, RF performed at site 2 and RBBB obtained during ablation. There was “A,” “H,” and “V” recorded at the ablation target; middle panel, ECG before ablation; right panel, right bundle conduction recovered after RF off. (B), left panel, RF performed at the atrial side of site 3 and caused RBBB during ablation; middle panel, narrow QRS tachycardia without RBBB induced before ablation; right panel, RBBB still existed at the end of the procedure. (C), left panel, RF performed at site 1 with small “A” potential and lead to RBBB; middle panel, narrow QRS observed during A-pacing before ablation (third beat); right panel, RB conduction recovered when RF terminated. RBB, right bundle branch.

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  Figure 3. Flowchart of ablation protocol in RAS and RMS group.* 1 patient gave up directly because of mechanical trauma-induced AV block and another one had AV block during ablation. RAS, right anteroseptal; RMS, right midseptal.

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  Figure 4. (A): Schematic representation of the septal region. (A): right anterior oblique (RAO) view. (B): left anterior oblique (LAO) view. The septal region usually is bounded superiorly by the His bundle (HBE) and inferiorly by the roof of the coronary sinus (CS). Dividing this area into three parts, para-Hisian accessory pathways occupy the superior third of the area and midseptal APs occupy the middle third. Site 2 and midseptal are the most risky sites, following with site 3 and site 1. (C): His-Purkinje anatomy with longitudinal dissociation and it was surrounded by a fibrous sheath, right bundle branch, and the left bundle branch close to each side of the endocardium. (D): left panel shows the overall view of the His-Purkinje system; the right panel shows the RF delivered at the para-hisian region, heat could transfer from the endocardium to the right bundle inside which could cause RBBB as consequence. AVN, AV node; IVC, inferior vena cava; TA, tricuspid annulus; MA, mitral annulus; HIS, His bundle; AP, accessory pathway; FP, fast pathway; RBB, right bundle branch; LBB, left bundle branch; LAF, left anterior fascicle; LPF, left posterior fascicle; ABL, ablation catheter; Endo,…