A case report of superior vena cava obstruction.

We report herein an 83-year-old gentleman with lung cancer who presented with nausea, complete atrioventricular (AV) block and presyncope. Despite a present temporary pacemaker, which had been inserted through the femoral vein 5 days previously, the patient had asystole attacks that resolved with atropine administration. Coronary angiography demonstrated no critical stenosis. Sick sinus syndrome was diagnosed, and permanent pacemaker implantation was decided. However, the guidewire could not be advanced into the superior vena cava (SVC). Right jugular venogram showed complete obstruction of the SVC. Subsequent computerized tomography also revealed its obstruction by a large lung tumor. Special attention should be given to patients with benign or malignant SVC syndrome before permanent pacemaker implantation.