Effect of operator experience on outcome of radiofrequency catheter ablation of accessory pathways.

R adiofrequency catheter ablation of accessory pathways has been shown to be safe and effective, and is rapidly becoming the treatment of choice for patients with the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardia involving a concealed accessory pathway. l4 Because radiofrequency catheter ablation requires skill in mapping and catheter manipulation, the outcome is at least in part operator-dependent. The purpose of this study was to determine the effect of operator experience on the outcome of radiofrequency catheter ablation of accessory pathways by analyzing the changes in efficacy and duration of the procedure as experience increased. The subjects of this study were the first 400 patients (164 female and 236 male; mean age 35 + 18 years, range 13 to 82) to undergo radiofrequency catheter ablation of an accessory pathway at the University of Michigan Medical Center between February 1990 and May 1992. No structural heart disease was present in 388 patients, 4 had coronary artery disease, 4 had Ebstein’s anomaly, and 4 had other types of heart disease. In each patient, a diagnostic electrophysiology test was pet$ormed in conjunction with catheter ablation. The abbreviated approach used for radiofrequency catheter ablation of accessory pathways at this institution was previously described. 2~5 Left free wall accessory pathways were approached from the ventricular aspect of the mitral annulus, and right free wall and septal accessory pathways were approached through the inferior vena cava. Catheter ablation procedures were performed by a team of 3 attending physicians and 8 electrophysiology fellows; the 3 physicians were continuously involved in the ablation program, whereas the 8 fellows participated in catheter ablation procedures for 6 to 18 months each. Catheter manipulation was pe$ormed primarily by the electrophysiology fellows. Mapping of accessory pathways, and identtjication of appropriate target sites for radiofiequency energy delivery were based on electrogram analysis pe$ormed by I attending physician. The equipment used for radiofequency catheter ablation procedures remained constant in all 400 patients. The catheters used for mapping and radiofrequency energy delivery all had a deflectable curve and 4 mm distal tip. In each patient, the duration of the ablation procedure (including the time needed for inserting and positioning catheters), the