三维电解剖标测指导疑难右侧游离壁旁路的导管消融

Objective To demonstrate the electroanatomic substrates of right-sided free wall (RFW)accessory pathways (APs) which were refractory to conventional catheter ablation utilizing three-dimensional (3D) mapping. Methods Seventeen patients with RFW APs that failed initial conventional catheter ablation(s)by a mean of 1～3(1.8±0.6) attempts were enrolled in the study. Electroanatomic mapping of the right atrium was performed during right ventricular pacing in 14 patients and orthodromic reciprocating tachycardia in 3patients. Radiofrequency energy was delivered via irrigation catheter to the earliest atrial activation site. Results The earliest atrial activation site, which represented the atrial insertion of the APs, was separated from the tricuspid annulus by an average of 9 ～ 20 ( 13.6 ± 3.4 ) mm, and the local activation time was 18 ～ 80(31.5±16.3) ms earlier than that of the corresponding annular point. The target electrogram demonstrated AP potential in fourteen patients and ventriculoatrial fusion in the rest three. Accessory pathway was blocked in one case during moving the catheter and RF ablation delivery on the areas. One patient exhibited an AP with wide branching on the atrial side during mapping. RF ablation with an irrigated catheter successfully interrupted AP conduction in remaining 16 patients without complications. After a mean follow-up of 3 ～ 41 (18.6±12.7) months, there were no recurrences of ventricular preexcitation or episodes of tachycardia. Conclusion RFW APs refractory to conventional catheter ablation might be due to unique anatomic AP features such as more epicardial course at the annulus level with atrial insertion distance from the tricuspid annulus. Electroanatomic mapping is helpful to accurately localize the atrial insertion sites of these APs and facilitates catheter ablation.

Right-sided free wall accessory pathway refractory to conventional catheter ablation: lessons from three-dimensional mapping