Three cases of right ventricular perforation and acute pericardial tamponade during transvenous pacemaker implantation and one case of chronic electrode penetration are reported. Successful repair was achieved via pericardiotomy in all cases with acute tamponade. Fragility of the myocardium in the elderly is considered to be the major reason for this complication which may occur despite the use of flexible electrodes and correct surgical technique. The relatively small intervention of inferior pericardiotomy appears to be the therapy of choice in case of tamponade. This approach should be feasible when transvenous pacemakers are implanted. Immediate availability of general anesthesia and postoperative intensive care appears to be manatory.