Technical Report of Radiofrequency Ablation of AVNRT with Persistent Left Superior Vena Cava: Success Relies on Basics

<b>Background/Objectives</b>: Persistent Left Superior Vena Cava (PLSVC) is a condition that may complicate the ablation of Atrioventricular nodal reentry tachycardia (AVNRT). We aimed to report technical experience in ablation under scuh clinical setting. <b>Methods</b>: 3D guided electrophysiological procedure was conducted and PLSVC was confirmed. Slow-pathway ablation for the AVNRT was performed and typical junctional rhythm during the ablation was observed. <b>Results</b>: Exactly the same AVNRT remained inducible after 10 radiofrequency applications, which was very likely because of suboptimal temperature increase due to lacking sustained stability/contact of the catheter given the PLSVC anatomy and the patient's deep respiration based on our observation during the RF applications. A non-steerable long sheath was introduced to achieve more firm contact of the ablation catheter, the slow-pathway was successfully ablated with just 1 application (seen immediately occurred, continuous typical junctional rhythms during ablation, and significantly better temperature during the ablation). <b>Conclusions</b>: PLSVC-related anatomical changes may destabilize ablation catheter making it difficult to establish sufficient energy delivery at the slow-pathway region and put forward the need for multiple ablations. Timely identifying such scenarios (e.g., insufficient stability, insufficient temperature) could help better plan/change the ablation technique or strategy to achieve better procedure outcomes. This technical report reminds us that typical junctional beats may not be the only determinant for successful ablation of the slow-pathway. The key to the solution often relies on basic ablation biophysics.