Thrombotic complications with pacemakers.

To analyze thrombotic complications, we performed brachial phlebographies in 100 consecutive patients (group 1), about 44 months after permanent pacemakers had been installed. Thirty-nine patients showed thrombotic lesions in the veins used to pass the stimulation electrode into the right ventricle. In 10 patients the medical history and in 12 patients clinical symptoms and signs indicated an impairment of venous flow. Fifteen of the 39 patients showed complete occlusion of one venous segment; collateral vessel formation was found dependent on the site and the extent of the occlusion. In the remaining 24 patients only partial occlusion without collateralization was demonstrated. Group 2 comprised 12 patients in whom the pacing lead originally inserted via right-sided veins had been severed and the free distal end left unsecured intraluminally when the second electrode was inserted via the left-sided cephalic vein. In all these patients phlebography about 19 months later revealed thrombotic complications, while 11 presented with clinical symptoms and signs. The incidence of thrombotic complications including segmental occlusion after the application of permanent pacer leads is only one-third of patients with segmental occlusion symptoms. However, since severed leads produce severe symptomatic complications in almost all cases their removal is mandatory.