B-AB10-05 PERMANENT DISTAL HIS BUNDLE PACING VIA PERSISTENT LEFT SUPERIOR VENA CAVA

His-purkinje conduction system pacing is widely used as a physiological pacing. Persistent left superior vena cava (PLSVC) is a relatively rare anatomic variation in clinic. Due to the distortion of its venous access, it is a challenge for operator to achieve precise His bundle pacing. Our study aimed to evaluate the feasibility of His bundle pacing in patients with PLSVC. N/A A 57-year-old female who had the indication of pacemaker implantation with sick sinus syndrome and paroxysmal atrial tachycardia was performed with His bundle pacing. PLSVC was found during the operation. The 3830-69 lead was used through C315HIS sheath (Medtronic Inc, Minneapolis, MN, USA) at first. However, either His bundle pacing or left bundle branch area pacing failed. Then we tried the 5076-58 active helix lead by adjusting the steel wire to double-curve shape in reverse and precisely located to His bundle. After electrode fixation, His potential and R wave with current of injury could be recorded, unipolar pacing at 0.5V/0.5ms captured only ventricular endocardium, and increased output at 1.0V/0.5ms captured His (in Fig). The R wave amplitude was 5.6mV and impedance was 570 Ω. The intraoperative electrophysiological characteristics, pacing parameters, UCG and CTA 3D reconstruction all indicated that the electrode was fixed to the ventricular side across the tricuspid valve. The threshold of His bundle was 0.5V/0.5ms on the first day after operation, and increased to 1.5V/0.5ms at two months follow-up. His bundle pacing was successfully achieved by 5076 active lead in the patient, which showed the conventional lead can achieve distal His bundle pacing via PLSVC.