[Mechanical complications of temporary pacemakers. Criteria for the diagnosis of perforation and dislodgement (author's transl)].

The methods used in the early diagnosis of catheter malposition are compared in 31 patients with temporary endovenous pacemaker. In all cases the heart and the pericardial space were observed either at surgery or at post-mortem examination. The patients were divided into three groups: Group A: eight patients with proof of perforation of the free wall of the right ventricule. Group B: eight patients with dislodgement of the catheter and dysfunction of demand and stimulation without signs of perforation. Group C: fifteen patients without neither dysfunction or perforation. Clinical, radiological and electrocardiographic data were evaluated in each group. With the exception of cardiac tamponade, there were no clinical symptoms distinguishing perforation from dislodgement. Radiologically, only important changes in catheter position had diagnostic value. ECG changes were not diagnostic. Endocavitary ECG permits to locate the catheter with respect to the right ventricular wall. A good contact with the endocardium determines the appearance of a pathologic wave in the distal electrogram which diminishes or disappears after perforation or dislodgement. In the group A patients the QRS was predominantly positive, a feature that was not observed in the other two groups. When the catheter backed up to the atrium, high voltage atrial potentials were registered. Although the analysis of endocavitary recordings constitutes the most useful method to detect catheter malposition, only the total clinical, radiological, and electrocardiographic data provide a firm diagnosis.