Challenges of Device Implantation in Persistent Left Superior Vena Cava with Right-Sided Aortic Arch

Abstract

The Case: A 62-year-old man with past history of anterior myocardial infarction and left anterior descending artery (LAD) stent (2012) with known right-sided aortic arch (type 2), presented with dyspnoea and syncope. Echocardiogram and MRI showed severe left ventricular dysfunction, ejection fraction 16%. ECG demonstrated Q waves in V1-V3, QRS duration 110ms and frequent non-sustained ventricular tachycardia, rate 200 bpm. Coronary angiogram showed LAD occlusion. Left-sided transvenous implantable cardioverter defibrillator (ICD) insertion was abandoned on identification of persistent left superior vena cava (SVC) draining into the large coronary sinus. Attempted right subclavian approach to right SVC failed due to inability to advance the proximal coil of the ICD lead into the right SVC. He had successful implantation of a subcutaneous ICD. Three months later he had an appropriate shock for monomorphic ventricular tachycardia, rate 220 bpm. Discussion: The co-existence of a right-sided aortic arch and persistent left SVC is unusual; a literature review revealed no similar cases. Persistent left SVC is the commonest congenital venous anomaly, occurring in 4.4% patients with congenital heart defects, typically atrial septal defects. It provides major challenges for transvenous lead insertion for implanted cardiac electrical devices, especially placement of the defibrillation coil for effective ICD shock delivery. The subcutaneous ICD provides effective defibrillation, but lacks the therapeutic option of anti-tachycardia pacing for painless ventricular tachycardia termination. Conclusion: Our case demonstrates that subcutaneous ICD insertion for secondary prevention of arrhythmia is a suitable alternative for patients with complicated venous anatomy.