Discussed in this study are the authors' experiences with electrostimulation of the heart. The study is based on 276 pacemaker operations performed in the past 7 years. The authors remain partial to the transvenously introduced endocardial pacemakers monitored by X-raj. When radiation symptoms manifested themselves in 2 team members, a revision was made in the procedure. As a result, the means by which one may be exposed to uncontrolled and, prolenged stron radiotion were cited. Such radiation can result in pathologic changes in the blood, damage to the skin, nails, germinative epithelium and bone marrow. To prevent such an outcome, certain precautionary measures are taken which protect both the patient and surgical team. Also mentioned is that the surgical personnel should have the same benefits as radiologists.