Inducibility of Atrial Fibrillation Before and After Radiofrequency Catheter Ablation of Accessory Atrioventricular Connections

Inducibility of Atrial Fibrillation. Introduction: The purpose of this study was to evaluate the inducihility of atrial fibrillation in patients with an accessory atriovcentricular connection (AAVC) and to determine if the inducibility of atrial fibrillation is altered after successfulradiofrequency catheter ablation of the AAVC. Methods and Results: Thirty‐seven patients with an AAVC and 36 control patients wereprospectively evaluated using a standardized atrial pacing protocol. The high right atrium waspaced using a 25‐beat drive train, 1.5‐second intertrain pause, 10‐mA pulse amplitude, and 2‐msec pulse duration at cycle lengths of 250 to 100 msec, in 10‐msec decrements. Pacing wasperformed twice at each cycle length. Thirty patients with an AAVC underwent repeat atrialoverdrive pacing after successful radiofrequency ablation of the AAVC. Atrial fibrillation wasinduced in 26 (70%) patients with an AAVC and 22 (61 %) controls (P = NS). Atrial flutter wasinduced in 26 (70%) patients with an AAVC and 22 (61%) controls (P = NS). The cumulativepercentage of patients with atrial fibrillation/flutter induced at each pacing cycle length was thesame in each group. There was no difference in the duration of atrial fibrillation/flutterbetween control patients and patients with an AAVC. Among the 30 patients who underwentrepeat atrial overdrive pacing after radiofrequency ablation of an AAVC, there was no difference in the inducibility or duration of atrial fibrillation/atrial flutter after ablation compared tobaseline. Conclusion: These findings indicate that the vulnerability of the atrium to fibrillate inresponse to atrial pacing is independent of the presence of an AAVC.