UNLABELLED: Catheter mapping and ablation of left accessory pathways may be difficult if the pathway fibre orientation is oblique across the mitral annulus. This is particularly true in case of concealed accessory pathway that conducts only in ventriculoatrial direction. The purpose of the study was to compare catheter ablation safety, efficacy, procedure and fluoroscopy times and number of radiofrequency energy deliveries for manifest and concealed left accessory pathways using retrograde transaortic approach. 56 patients (26 females) aged 41.6 +/- 15.1 years underwent 59 ablation procedures for 59 left accessory pathways. 25 (44.6%) patients with 27 concealed accessory pathways and additional 2 patients with a manifest pathway mappable only during retrograde conduction formed group I and were compared to 29 patients with a manifest accessory pathway mappable during ventricular preexcitation (group II). Ablation was acutely successful in all patients. Reablation was necessary for the pathway recurrence in 2 patients and for a different pathway in 1 patient. Deep femoral venous thrombosis complicated ablation in 1 patient. During the 14.9 +/- 8.2 (3-30) month follow-up period all the patients remain free of a pathway related tachyarrhythmia. Both the groups (I vs II) did not differ in procedure (180 +/- 76.7 vs. 187 +/- 75.8; p = 0.36) and fluoroscopy (25.3 +/- 18.6 vs. 33.5 +/- 24.7; p = 0.08) times (min) and number of radiofrequency energy deliveries (10.0 +/- 9.2 vs. 10.2 +/- 9.8; p = 0.46).

CONCLUSION: Transaortic approach to the left concealed accessory pathways is safe and effective in virtually 100% of patients and, compared to manifest pathways, does not prolong procedure and fluoroscopy times nor the number of radiofrequency energy deliveries.

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