Electroanatomical properties and high-density mapping guided targeted isolation of superior vena cava

INTRODUCTION: Superior vena cava isolation (SVCI) is associated with complications such as sinus node (SN) and phrenic nerve (PN) injury or SVC stenosis. Our study assessed the electrophysiological properties of the SVC and use of high-density mapping for targeted SVCI by ablating preferential conduction sites to avoid these complications. METHODS: Eighty-three consecutive patients, undergoing HD mapping of the SVC during AF re-ablation procedures were prospectively included. Conduction block (CB) lines between the right atrium and SVC, location of the sinus node (SN) and phrenic nerve (PN), and their spatial relationship to the ablation line (AbL) were assessed. RESULTS: CB lines were present in 98% of patients, with gaps identified in all SVC segments, most frequently posterior (73%), with a median gap width of 23.9 (14.3-37.8) mm. All gaps expressed decremental properties in the EP study. Ablation was performed in 35 (42%) patients and was achieved in all cases using targeted segmental ablation, closing the gaps between the CB lines.Median ablation duration was 88 (66; 161) seconds with a median of 8 (6-12) radiofrequency applications. SN was separated from SVC with CB line in 98% of cases, what excluded necessity to ablate in this area, distance from the AbL to the SN exit zone was 8.9 (6-14.7) mm. PN was located outside the areas of preferential conduction in all cases, distance from AbL to the PN was 10.4 (6.7-12.1) mm. No complications occurred. CONCLUSIONS: HD mapping-guided, targeted segmental SVCI using RF energy is feasible and safe.