[Uni- and bipolar 2-chamber stimulation with a DDD system of programmable polarity].

In order to compare bi- (b) and unipolar (u) stimulation, sensing and electrical interference, twelve patients were followed over a period of ten months. The implanted device was the CPI Delta 925, programmable to the bi- and unipolar mode in the atrium (a) as well as in the ventricle (v). A CPI-4266 screw-in lead positioned in the atrium and a CPI-4260 hook lead placed in the ventricle were connected to the pacemaker. Intraoperatively determined were: (1) the threshold at pulse durations of 0.1 ms, of 0.5 ms and of 1.0 ms, (2) the P/QRS-amplitude, (3) the slew-rate and (4) the resistance in both the bi- and unipolar mode. Having programmed the atrial sensitivity to 0.25 mV or to 0.75 mV and the ventricular sensitivity to 0.5 mV or to 1.5 mV, we postoperatively examined and compared in the two modes of polarity the threshold (2.2 V and 5 V), the P/QRS-amplitude and finally the electrical interference triggered with the help of chest wall stimulation. All measurements were performed one day, four weeks and four months after implantation.(ABSTRACT TRUNCATED AT 250 WORDS)