[Pacemaker implantation via a persistent left superior vena cava in atresia of the true superior vena cava].

Implantation of a single-chamber pacemaker was planned in an 83-year-old woman with sick-sinus syndrome causing dizziness, bradycardia and tachycardia. After puncture of the right subclavian vein it proved impossible to advance a guide-wire into the superior vena cava, under fluoroscopy the wire always being seen to coil in the left subclavian vein and hence passing into a caudally directed vein. This vessel proved to be a persistent left superior vena cava (PLSVC) which connected to a markedly dilated coronary sinus (2 cm diameter) opening into the right atrium. An 85-cm electrode was then passed via the PLSVC and right atrium into the right ventricle without difficulty and was anchored in its apex. Echocardiography failed to reveal any further anomaly. Three-dimensional computed tomographic reconstruction established atresia or agenesis of the (right) superior vena cava. Normal pacemaker function freed the patient of all symptoms postoperatively.