Atrioventricular Node Reentrant Tachycardia in Patients With Congenitally Corrected Transposition of the Great Arteries and Results of Radiofrequency Catheter Ablation

BACKGROUND: We sought to investigate the feasibility of radiofrequency catheter ablation of atrioventricular node reentrant tachycardia and the ideal site for slow pathway (SP) ablation in congenitally corrected transposition of the great arteries. METHODS AND RESULTS: Nine patients with congenitally corrected transposition of the great arteries referred for catheter ablation of atrioventricular node reentrant tachycardia were studied. A single His potential was recorded in 8 patients (89%, 6 S, L, L and 2 I, D, D). The earliest atrial activation during retrograde atrioventricular node conduction occurred at His bundle region (HBE; n=7) or shifting from HBE to coronary sinus ostium (n=1, S, L, L). Two anatomically separate His potentials were recorded in 1 patient (11%, S, L, L), one at the anteroseptum (HBE-1) and the other at the confluence of the pulmonary and mitral annulus (HBE-2). In 8 cases with a single His potential recorded, SP was abated at the posterior-midseptum, 2 (S, L, L) at the right posteroseptum, 1 (S, L, L) at the left posteroseptum, and 5 (3 S, L, L and 2 I, D, D) at the midseptum after failure of energy application at the posteroseptum. Junctional rhythm was observed during radiofrequency catheter ablation in all 8 of the cases. In the remaining patient with 2 anatomically separate His potentials recorded, SP was successfully ablated from the confluence of the pulmonary and mitral annulus, slightly below the HBE-2. Junctional rhythm was also induced during radiofrequency catheter ablation. CONCLUSIONS: In S, L, L or I, D, D, radiofrequency catheter ablation of atrioventricular node reentrant tachycardia is feasible. SP input region can mainly be found in the posterior midseptum, especially in patients with single penetrating atrioventricular nodes. SP could usually be successfully ablated in these regions.