Retrograde fast pathway cryoablation inside the coronary sinus for slow-fast atrioventricular nodal reentrant tachycardia in a patient with persistent left superior vena cava.

Introduction: Persistent left superior vena cava (PLSVC) is accompanied by enlarged coronary sinus (CS) and deformation of the triangle of Koch. This makes anatomical evaluation of the atrioventricular (AV) nodal pathways difficult.

Methods: We attempted cryoablation of retrograde fast pathway located in the enlarged CS roof of PLSVC for slow-fast AV nodal reentrant tachycardia (AVNRT) induced by inadvertent antegrade fast pathway elimination during ablation of left atrial tachycardia.

Results: Slow-fast AVNRT was successfully eliminated without AV block progression.

Conclusions: This is the first case of successful retrograde fast pathway ablation of the CS ostial roof for slow-fast AVNRT with PLSVC.