[Superior vena cava syndrome: a rare complication of endocavitary cardiac pacing].

The superior vena cava syndrome is an exceptionally rare complication of endocavitary cardiac pacing, asymptomatic venous thrombosis being much more common. Two cases wee observed as late complications of pacemaker implantation. In the first case the clinical signs regressed with the development of a collateral circulation under heparin therapy after failure of fibrinolytic drugs. In the second one, the severity of the superior vena cava syndrome and the poor quality of the collateral circulation led to the implantation of a Gore-Tex prosthesis. This surgical bypass led to a rapid and complete regression of the clinical signs. It would seem to be a valuable alternative when anticoagulant therapy fails.