With transvenous intracardiac implantation of pacemakers after a few days already a fibrotic wall has developed around the impulse generator by a chronical proliferous process. Where the electrode has been advanced through the vein-wall and in the following veins the cable is wrapped cuff-like by increased collagenous fibres. Frequently these formed an adhesion with the inner vein-wall for quite some distance. Inside the heart, adhesion to the tricuspid valve may lead to insufficiency of this. The incorporation in the myocardium occurs as embedding in connective tissue. Here also chronical proliferous processes occur obviously. The electric conductiveness in the primary thrombo-cellular state after implantation is reduced rather than in late phase of hyaline building. In 12 instances of autopsy, 4 persons died a non-natural death (suicide). In one case, technical failure caused death, and once pulmonary embolism. In the other cases, the basic ailment seems to have been fatal. In four of these 6 instances, the scale of myocardial and endocardial tissue response to the pacemaker have aggravated certainly the prior process of disease. In conclusion, discerning opinions on fitness and safety in traffic and on the limitations of these therapeutical measures are ventilated.