Azygos continuation of interrupted inferior vena cava in association with sick sinus syndrome.

Various diagnostic and therapeutic procedures of the right side of the heart and the systemic venous system have increased the need for ready access to the inferior vena cava (IVC) through the transfemoral route. Anatomical variations or obstruction of the IVC can make these procedures difficult. The case of 47 year old woman with an interrupted infrahepatic IVC with azygos continuation accompanied by sick sinus syndrome and a structurally normal heart is reported. Negotiating a temporary pacing lead from the IVC to the right atrium was difficult. Ultimately, the lead took the course from the IVC to azygos vein to superior vena cava to right atrium to right ventricular apex. Permanent VVI pacing through the right subclavian route was uneventful, as the superior vena cava and its tributaries had a normal course. An awareness of the existence of these anomalies before pacing can lead to the use of an alternative route for pacing, which may avoid undue delay of an otherwise urgently needed procedure.