Electrical anatomic structure of superior vena cava under high-resolution mapping

Objective To explore the electrical anatomic structure of superior vena cava (SVC) in sinus rhythm. Methods Twenty-four atrial fibrillation patients who received circumferential pulmonary vein isolation (CPVI) underwent high-resolution mapping in sinus rhythmin Cardiac Arrhythmia Center, Fuwai Hospital form January 2018 to June 2018. The location of sinus node and phrenic nerve and electric breakthrough points were noted. Then the connection between right atrial to SVC were ablated under the guide of circular catheter. Results Sinus nodes varied in location (lateral: 75%, anterior: 12.5%, posterior: 12.5%) , while phrenic nerve (PN) are predominantly located in lateral wall (87.5%) with few in the posterior wall (12.5%) . The successful ablation points are mainly in anterior wall and posterior septal wall. After ablation, the heart rate increased from (74.5±14.6) bpm to (81.0±13.0) bpm (P=0.007) . Twenty-three (95.8%) patients received superior vena cava isolation (SVCI) , only one case failed to perform ablation due to the location of PN and breakthrough site were at the same spot. Patients who received SVCI didn’t have any complications like SN injure, PN injure and SVC stenosis, and so on. Conclusion The location of SN is varied from individuals, however, the successful SVC isolation sites are located in anterior wall and posterior septal wall . SVC isolation under the guidance of high-resolution is safe and effective. Key words: Vena cava, superior; Sinus node; Phrenic nerve; High-resolution map