Ablation of left-deviated dual atrioventricular nodal pathway from coronary sinus

Variation of dual atrioventricular nodal pathway is one of common reasons of misdiagnosis, failure of ablation or recurrence of atrioventricular nodal reentrant tachycardia (AVNRT). We report one case of atypical AVNRT associated with an unusual left side deviation of atriventricular node and dual AV nodal pathway, which received an unsuccessful ablation attempt before. His bundle potential was prominent when recorded from left side of the inter-atrial septum but not from right septum. Radiofrequency energy attempts failed at several routine sites including the ostium of the coronary sinus. But the ablation was finally successful deep in the coronary sinus.