Radiofrequency ablation in multiple accessory pathways and the physiologic implications.

The presence of multiple accessory pathways was noted in 24 of 210 consecutive patients (12 males and 12 females aged 15 to 77 years [mean +/- SD 43 +/- 16]) with the Wolff-Parkinson-White syndrome who underwent electrophysiologic study and radiofrequency ablation. Six had 3 and 18 had 2 accessory pathways. There were 25 manifest and 29 concealed accessory pathways. The location of the accessory pathways was in the left free wall in 22, the right free wall in 17, the left posterior portion of the ventricular septum in 8, the right posterior portion of the ventricular septum in 6, and the midseptum in 1. The success rate of accessory pathway ablation and the fluoroscopic time in these 24 patients with multiple accessory pathways were 89% and 78 +/- 66 minutes, respectively, whereas they were 98% (p < 0.01) and 36 +/- 37 minutes (p = 0.01) in the 186 patients with a single accessory pathway. The mean applications, the power level of the radiofrequency current and the application duration in these 24 patients were 21 +/- 22, 30 +/- 3 W, and 27 +/- 10 seconds, respectively. In the 186 patients with a single accessory pathway, they were 9 +/- 12 applications (p = 0.02), 30 +/- 4 W (p = NS) and 26 +/- 9 seconds (p = NS), respectively. Seventeen of the 24 patients had a follow-up electrophysiologic study 89 +/- 40 days after ablation, and 2 (12%) had resumption of a right and left accessory pathway conduction.(ABSTRACT TRUNCATED AT 250 WORDS)