Catheter Ablation of Left Parietal Accessory Pathways

Fifty‐one patients with a left parietal pathway and drug refractory tachycardia underwent transcatheler ablation of their accessory pathway. Three had single concealed pathways, two had multiple pathways, and the remaining 46 had the Wolff‐Parkinson‐While syndrome. Two patients were resuscitated from a cardiac arrest related to a ventricular fibrillation. A multipolar (quadri‐, hexa‐, or octopolar) electrode catheter was positioned within the coronary sinus in order to localize the pathway accurately. An ablation catheter was then introduced either through a patent foramen ovale (11 patients), by transseptal catheterization (14 patients) or a retrograde arterial catheterization (26 patients). The mitral annulus was mapped with this catheter during orthodromic tachycardia in order to record ventriculoatrial (VA) time as short as (or even shorter than) that recorded in the coronary sinus. The VA time in our series was 82 ± 13 msec. Two 160‐joule cathodal shocks were delivered at this site and eventually repeated according to the results (73 sessions/51 patients). The mean cumulative energy was 650 ± 205 joules. No significant side effects occurred except one case of a right coronary artery spasm leading to inferior wall infarction. During follow‐up of 2–49 months, all but two patients were free of tachycardia. Twelve patients were reassessed 4 to 8 months after the procedure: conduction over the pathway was absent, and no vascular damage was noticed. Catheter ablation of left parietal accessory pathways is both effective and safe. Ablation by retrograde arterial catheterization was as efficient as the tranxseptal approach. This method is an attractive alternative to surgery.