Closed-chest ablation of left lateral atrioventricular accessory pathways

Thirty patients with a left lateral accessory pathway and drugrefractory tachycardia underwent attempted transcatheter ablationof the accessory pathway. Three had a concealed accessory pathwayand 27 had the Wolff-Parkinson-White syndrome. A quadripolarelectrode catheter was positioned within the coronary sinusin order to locate the earliest retrograde atrial activationduring orthodromic reciprocating tachycardia. The appropriatebipole was used as the radiographic and electrophysiologic referenceof the insertion of the accessory pathway. A catheter was thenintroduced 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 transaorticapproach (10 patients). The mitral annulus was mapped with the left atrial catheterin order to record a synchronous or earlier atrial deflectionthan reference during reciprocating tachycardia. VA' time atthe preablation site was 82 ± 12 ms. Two to seven 160J cathodal shocks (650 ± 205 J cumulative per patient)were delivered at this site in 38 sessions. No significant side-effectsoccurred except for one case of right coronary artery spasmleading to inferior wall infarction. Following fulguration, accessory pathway conduction was abolishedin all patients but one with a second accessory pathway. Duringfollow-up of 1–34 months, all patients but one were freeof tachycardia: reciprocating tachycardia recurred in one patient,who had a concealed accessory pathway, on the third day. Accessorypathway conduction, assessed in 10 other patients 3–26months after the procedure, was absent. Coronary arteriographyperformed in seven patients was normal. Catheter ablation of left free-wall accessory pathways is bothsafe and effective with shocks directly delivered to the mitralannulus through a transseptal or transaortic catheter. It isan attractive alternative to surgical ablation of these accessorypathways.