RADIOFREQUENCY CATHETER ABLATION OF CONCE ALED LEFT-FREE WALL ATRIOVENTRICULAR ACCESSORY PATHWAYS WITHOUT CORONARY SINUS CATHETERIZATION

Background. Radiofrequency catheter ablation of concealed left-sided a ccessory pathways conventionally implies the introduction of several c atheters for the assessment of electrophysiological properties as well as for the localization of the accessory pathways. Patients and metho ds. Feasibility of radiofrequency ablation using a simplified two-cath eter technique without coronary sinus catheterization was prospectivel y studied in 95 consecutive patients with a single concealed left free -wall accessory pathway. A 6F quadripolar catheter was introduced into the right atrium/right ventricle and tachycardia was induced by elect rical stimulation. The presence of a concealed left-sided accessory pa thway was suggested electrocardiographically (negative P wave in I and /or aVL during orthodromic tachycardia) or by earlier atrial activatio n in the pulmonary artery compared to the right atrium. Mapping of the mitral annulus and ablation were performed during orthodromic tachyca rdia or ventricular pacing using a 7F steerable catheter. Radiofrequen cy energy was applied at sites with the shortest VA interval, The proc edure was considered effective if tachycardia could not be induced and if VA dissociation or exclusive nodal VA conduction were observed. Re sults. The procedure was initially successful in 93 out of 95 patients (98%). Mean number of applications were 3.2 +/- 2. Mean fluoroscopy t ime and total procedure duration were 14 +/- 9 and 108 +/- 33 minutes respectively. At a mean follow-up of 21 +/- 13 months, 2 patients requ ired a second session because of tachycardia recurrence. Conclusions. Radiofrequency catheter ablation of concealed left-sided accessory pat hways can be safely, effectively and rapidly performed using a two-cat heter technique without coronary sinus catheterization.