Noncontact Mapping Guided Ablation of Atrioventricular Nodal Reentrant Tachycardia in a Patient with Persistent Left Superior Vena Cava

Abstract

We described a successful slow-pathway (SP) ablation in a 30-year-old woman with persistent left superior vena cava (PLSVC) guided by 3-dimensional noncontact-mapping (NCM) system. She presented with frequent episodes of poorly tolerated paroxysmal supraventricular tachycardia. The course of the CS catheter was unusual, and the presence of PLSVC with right superior vena cava atresia was documented by venography. The baseline electrophysiologic study indicated the presence of common type AV nodal reentrant tachycardia (AVNRT). By anatomical approach, SP ablation was initially performed in the posteroinferior region of Koch triangle near the CS ostium, but AVNRT was still inducible. In order to avoid extensive ablation and the risk of AV node injury, we introduced a multielectrode array catheter for a NCM approach. We determined the earliest atrial activation area of the retrograde conduction using ventricular extrastimulation. To locate the SP, a right ventricle extrastimulus pacing with S1S1 interval 500 ms, and S1S2 interval started from 450 ms with a 10 ms decrement. In this way, the retrograde slow and fast pathway can be identified from the earliest atrial activation with a rS pattern on the virtual electrograms. Successful ablation was achieved at the site of retrograde SP with an accelerated junctional rhythm observed during RF application. After slow pathway ablation, dual AV nodal physiology disappeared, and AVNRT became non-inducible.