The bipolar catheter pacemaker was used as a temporary measure in 58 patients with complete heart block. The external jugular veins were the preferred sites of passage, and a fluoroscopic image intensifier was almost a necessity. Complications were frequent including two deaths during catheterization and two later deaths. Failure to pace was usually caused by malposition or breakage of the catheter, poor electrical connections, or run-down batteries. Investigation of such failure should include a survey of the pacemaker artifact in the standard electrocardiogram and the recording of endocardial leads from the catheter, in addition to x-ray studies.