Four Years Experience with the Bisping Transvenous Pacemaker Electrode

From October 1978 to March 1983 843 Bisping transvenous screw in pacemaker electrodes have been implanted at the surgical University Clinic of Graz/ Austria. The Medtronic 6957 polyurethane coated electrode is placed into the right ventricle or atrium with the screw retracted in the insulating cover. When the desired electrode position is reached, the screw at the electrode tip is protruded by application of a torque at the external end of the conductor coil. In the ventricular position, stimulation threshold was a mean 0.7 Vat 0.5 msec impulse width, the incidence of electrode instability was 1.1%. Reintervention for exit block became necessary in 2.0%. In atrial position (96 cases) the mean stimulation threshold was 1.1 Vat 0.5 msec impulse width, the rate oflead dislocation was 3.1%. When extraction of the electrode became necessary in 8 cases due to infection, the screw at the electrode tip could be retracted in all cases, up to 6 months after implantation. In 3 cases, however, permanent traction of 50–100 grams for up to 72 hours had to be applied to remove the lead tip from the superior caval vein. In a group of 17 patients, in whom implantation was carried out before March, 1979, no electrode related problems were observed. Until now, we did not observe a single case of electrode dysfunction due to damage of the polyurethane cover or because of fracture of the unifilar conductor coil. The Bisping transvenous pacemaker electrode has largely reduced the risk of electrode dislocation and thus has contributed to safety in ventricular, atrial and bifocal pacing.