Long-term cardiac pacing with permanent transvenous electrodes has achieved wide acceptance with only occasional reports of venous obstruction and edema. To determine the incidence of venous abnormalities associated with transvenous electrodes, 34 venograms were obtained in 32 patients paced 18 months or longer. Eleven venograms demonstrated severe obstruction with collateral circulation communicating with the opposite cervical and innominate venous channels; 7 of these showed total occlusion. Seven venograms revealed no obstruction. The remaining 16 venograms showed venous stenosis without collaterals. It is concluded that venous abnormalities associated with permanent transvenous pacing occur commonly but are not usually associated with arm or facial edema.