LAUSR

BACKGROUND The Senning and Mustard operations for dextro-transposition of the great arteries are associated with an increased risk for supraventricular tachycardia. Catheter ablation has been shown to be acutely successful for achieving rhythm control in this population, but the mechanisms of recurrence are ill-defined. OBJECTIVE We hypothesized that the type and degree of recurrence would vary by the surgical technique used. METHODS All consecutive catheter ablation procedures for dextro-transposition of the great arteries after the Mustard or Senning operation between 2004 and 2016 at a single center were reviewed. Tachycardia mechanisms were determined by complete 3-dimensional mapping in addition to a standard electrophysiological technique for all cases. RESULTS Twenty-eight patients underwent 38 procedures during the study period. The most common mechanism at the index procedure was intra-atrial reentrant tachycardia using the cavotricuspid isthmus. Over a median follow-up period of 1.6 years, 9 patients experienced recurrent tachycardia (32%), all of whom underwent repeat catheter ablation. Tachycardia recurrence was more common after the Senning vs the Mustard operation (6 of 10 [60%] vs 3 of 18 [17%]; P = .034). In addition, substrates for recurrence were different from those encountered at the index procedure in 10 of 13 tachycardias (77%), with the single most common location being the posterior anastomosis after the Senning operation. Complete control was ultimately achieved in 27 patients (96%) when considering all procedures. CONCLUSION Recurrent tachycardia after catheter ablation appears to be more common after the Senning operation and to involve substrates unique to this repair. The posterior anastomosis is commonly implicated and should not be overlooked.