Sinus node dysfunction associated with absence of right superior vena cava.

Abstract
A 41 yr old man presented with dizziness associated with sinus bradycardia and sinus arrest. Implantation of a transvenous pacing lead was frustrated by the absence of the right superior vena cava. The left superior vena cava persisted and drained via the coronary sinus into the right atrium. Absence of the right superior vena cava may present with symptomatic sinus node dysfunction and may require an epicardial demand pacing system.