Exploring Dual Chamber Pacemakers in the Presence of Persistent Left Superior Vena Cava: Two Case Reports
Résumé
Aims: To report two cases of persistent left superior vena cava (PLSVC) diagnosed during pacemaker implantation and emphasize its clinical relevance and procedural implications. Introduction: PLSVC is the most common thoracic venous anomaly, often asymptomatic and discovered incidentally. It may be associated with arrhythmias or conduction disorders and complicates cardiac device implantation due to its atypical venous course. Case Presentation: We present two male patients, aged 82 and 65, admitted for bradyarrhythmia-related symptoms. Both underwent transthoracic echocardiography revealing a dilated coronary sinus, raising suspicion of PLSVC. During pacemaker implantation via the left subclavian vein, the guidewires took an unusual path through a PLSVC and coronary sinus into the right atrium. The first case involved an isolated PLSVC with absent right SVC. In both cases, pacemaker leads were successfully positioned with satisfactory thresholds. Discussion: Although PLSVC occurs in only 0.3–0.5% of the general population, it is more common in patients with congenital heart disease. Its presence may lead to procedural challenges due to the acute angle between the coronary sinus and tricuspid valve. The presence of a retro-aortic innominate vein may further complicate catheter manipulation and increase the risk of venous injury. A dilated coronary sinus is a key echocardiographic clue, and contrast studies or CT/MRI may confirm the diagnosis. Conclusion: PLSVC should be suspected in patients with an enlarged coronary sinus. Its presence requires awareness and adapted techniques during device implantation to avoid complications and ensure procedural success.