Superior Vena Cava Perforation During Atrial Lead Implantation in a Patient With Repaired Tetralogy of Fallot: a Case Report

Abstract Background Superior vena cava (SVC) injury during pacemaker implantation is rare, with most cases reported during lead extraction rather than placement. In adults with congenital heart disease (ACHD), unexpected resistance during lead advancement requires immediate reassessment because technical or device-related factors can cause venous injury even when pre-procedural imaging does not show hostile venous anatomy. Evidence on the management of venous injury during implantation is limited. Case Presentation A 62-year-old woman with repaired TOF presented with recurrent syncope. An implantable loop recorder documented a 10-second sinus pause. She underwent elective dual-chamber pacemaker implantation. Left subclavian venous access was obtained, and the right ventricular lead was positioned without difficulty. During advancement of the atrial lead, resistance was encountered at the subclavian-SVC junction, and the lead was withdrawn. Intraprocedural venography demonstrated focal contrast pooling at the SVC-azygos junction with mediastinal extravasation, concerning for SVC dissection or contained perforation. The patient remained haemodynamically stable. Transthoracic echocardiography showed no pericardial effusion. Non-contrast computed tomography of the chest confirmed mediastinal contrast adjacent to a patent SVC without obstruction or thrombosis. Conservative management with close observation was undertaken. Repeat CT imaging after 24 hours demonstrated complete resolution. Inspection of the atrial lead revealed unintended extension of the active-fixation screw, suggesting a mechanical mechanism for venous injury. Discussion This case highlights a rare but important complication of pacemaker implantation in ACHD. The normal pre-procedural venous assessment, uncomplicated right ventricular lead placement, and unintended extension of the atrial lead fixation screw support a device-related mechanical mechanism rather than anatomical difficulty. It emphasises immediate cessation of advancement when resistance occurs, lead inspection with confirmation of screw retraction, early venography, and conservative management in haemodynamically stable patients with a patent SVC.