Closed-chest ablation of left lateral atrioventricular accessory pathways.

Thirty patients with a left lateral accessory pathway and drug refractory tachycardia underwent attempted transcatheter ablation of the accessory pathway. Three had a concealed accessory pathway and 27 had the Wolff-Parkinson-White syndrome. A quadripolar electrode catheter was positioned within the coronary sinus in order to locate the earliest retrograde atrial activation during orthodromic reciprocating tachycardia. The appropriate bipole was used as the radiographic and electrophysiologic reference of the insertion of the accessory pathway. A catheter was then introduced into the left atrium, through a patent foramen ovale (six patients) or after transseptal catheterization (14 patients) according to Croft's technique, or using a retrograde transaortic approach (10 patients). The mitral annulus was mapped with the left atrial catheter in order to record a synchronous or earlier atrial deflection than reference during reciprocating tachycardia. VA' time at the preablation site was 82 +/- 12 ms. Two to seven 160 J cathodal shocks (650 +/- 205 J cumulative per patient) were delivered at this site in 38 sessions. No significant side-effects occurred except for one case of right coronary artery spasm leading to inferior wall infarction. Following fulguration, accessory pathway conduction was abolished in all patients but one with a second accessory pathway. During follow-up of 1-34 months, all patients but one were free of tachycardia: reciprocating tachycardia recurred in one patient, who had a concealed accessory pathway, on the third day. Accessory pathway conduction, assessed in 10 other patients 3-26 months after the procedure, was absent. Coronary arteriography performed in seven patients was normal.(ABSTRACT TRUNCATED AT 250 WORDS)