The main objective was to assess electrophysiological parameters which may be important for effective radiofrequency ablation of accessory atrioventricular pathways. In a group of 66 patients a total of 490 applications of radiofrequency current were made, incl. 68 which led to successful severing of the accessory pathways. The ablations were successful in 65 patients (98.5%). The potential of the accessory pathways was present in effective ablations in 19 cases of 68 applications (28%), while in ineffective ablations it was present in 13 cases of 421 applications (3%, p < 0.001). Stability of the electrogram was found in all 68 effective ablations (100%), while in ineffective ablations a stable electrogram was found in 248 cases of 323 applications (77%, p < 0.001). In unstable electrograms the ablation was not effective in any of the patients. The V-delta interval was significantly longer in successful ablations (16 +/- 14.2 ms) than in unsuccessful ones (3 +/- 19.4 ms, p < 0.001). The ventriculoatrial interval was in successful ablations significantly shorter (57.5 +/- 22.5 ms) than in unsuccessful ones (74.5 +/- 20.9 ms, p < 0.001). In 90% applications the ventriculoatrial interval was less than 70 ms. Of 10 evaluated parameters the potential of the accessory pathway, stability of the electrogram, V-delta interval (equal or < or = 0) and short ventriculoatrial intervals (equal to or < or = 70 ms) proved important parameters for successful ablation of accessory pathways.

Keywords: Adolescent; Adult; Aged; Catheter Ablation; Electrocardiography; Electrophysiologic Techniques, Cardiac; Female; Heart Conduction System /surgery/; Humans; Male; Middle Aged; Tachycardia, Atrioventricular Nodal Reentry /physiopathology/; Treatment Outcome