Forced Intraoperative Modification of Permanent Cardiac Pacing Tactics Through Persistent Left Superior Vena Cavata in a High-Risk Patient for Cardiac Surgery: A Case Report

Rationale. Implantation of permanent pacemakers in patients after repeat cardiac surgery can be significantly limited by cicatricial changes, recent cannulations, and obliteration of conventional venous accesses. An additional complication is the presence of congenital variants of systemic venous return, primarily persistent left superior vena cava (PSVC), which alters the geometry of endocardial electrode placement and increases the risk of technical complications. Case Description: This patient presented with a complex cardiac surgical history: aortic coarctation reconstruction in 2013, David I surgery in December 2025, and subsequent emergency hospitalization for decompensated chronic heart failure secondary to aortic valve avulsion and severe aortic regurgitation. On June 10, 2026, the patient underwent repeat aortic valve replacement with a Perceval L seamless biological valve prosthesis for life-saving reasons. In the early postoperative period, manifestations of sick sinus syndrome persisted, with transient second-degree sinoatrial block and pauses up to 3950 ms. Therefore, implantation of a dual-chamber, rate-adaptive pacemaker was planned for June 12, 2026. Intraoperatively, the standard right-sided approach was deemed unacceptable due to a fresh postoperative wound, severe tissue edema, and recent cannulation of the right subclavian artery. Upon conversion to the left subclavian approach, a stented septal vein (SVC) was detected with drainage through the dilated coronary sinus into the right atrium. Given preserved atrioventricular conduction, severe hypocoagulation, thrombocytopenia, and a high risk of coronary sinus injury, a decision was made to abandon the ventricular lead and perform single-chamber atrial pacing in AAIR mode. The lead with active fixation was successfully advanced through the splanchnic vein and the coronary sinus into the right atrium. Conclusion. This clinical observation demonstrates that in a patient with sick sinus syndrome and preserved atrioventricular conduction, AAIR mode can be a reasonable and technically safe option for permanent pacing when standard venous access is impossible and there is a high risk of ventricular lead placement through an anomalous venous collector.