[The diagnosis and ablation of accessory atrioventricular pathways in the initial electrophysiological exam: a new therapeutic modality in pre-excitation syndromes].

OBJECTIVE: To describe the experience and results in the diagnosis and catheter ablation of atrioventricular accessory (AP) pathways during the initial electrophysiologic study. DESIGN: We performed catheter ablation at the time of an initial electrophysiologic study in 22 consecutive patients (12 W and 10 M, mean age 42 +/- 15) with Wolff-Parkinson-White syndrome or supraventricular tachycardia. SETTING: Cardiology Department at University Hospital. INTERVENTIONS: The precise AP mapping was performed with the ablation catheter (4 mm distal electrode and deflectable tip) according to the earlier ventricular activation during sinus rhythm or the earlier atrial activation during ventricular pacing or orthodromic reentrant tachycardia. For left-sided pathways the ablation catheter was positioned on the mitral annulus retrogradely across the aortic valve, while for right-sided pathways it was positioned on the tricuspid annulus or near the coronary sinus os. Radiofrequency energy was applied for 20-60 segs with 55-65 Volts. MEASUREMENTS AND RESULTS: Seventeen AP were manifest and five were concealed. AP were left lateral in 11 patients (50%), left posterior in 5, and right postero-septal, right posterior or antero-septal in 2 patients each. The ablation was initially successful in 18/22 (82%), with 9 +/- 8 radiofrequency applications. Mean duration of the entire procedure was 145 +/- 59 min and the fluoroscopy duration was 39 +/- min. There were no major complications. During 2-9 months of follow-up AP conduction returned in two patients. CONCLUSIONS: Radiofrequency catheter ablation of AP is effective and safe and can be performed at the time of an initial electrophysiologic test, avoiding the need for long-term antiarrhythmic drug therapy or surgical ablation.