Automatic adjustment of pacemaker stimulation output correlated with continuously monitored capture thresholds: a multicenter study. European Microny Study Group.

Pacing threshold is affected by many factors. A pacing system able to confirm capture at each beat and automatically adjust its output close to the actual pacing threshold is highly desirable. This study evaluates the safety and efficacy of the Autocapture function of the Pacesetter Microny SR+. One hundred thirteen patients were recruited from 16 centers in 7 European countries and followed up for 1 year. All pacemakers were implanted with Pacesetter's low polarization, bipolar leads. The key feature of Autocapture is the immediate delivery of a 4.5 V safety backup pulse 62.5 ms after any ineffective ongoing low output pulse. Holter recordings confirmed total reliability of this feature without any exit block. The measured evoked response (ER) signal was stable over time. Acute and chronic pacing thresholds measured by VARIO and Autocapture tests correlated (r > 0.79) over the period of the study. The incidence of backup pulses was 1.1% during pacing. With Autocapture programmed ON, the overall total current consumption was 4.1 microA for VVI and 5.0 microA for VVIR pacing. This study proved that the Autocapture safely and reliably regulates the pacemaker's output according to the prevailing threshold thus providing maximum patient safety and prolonging service life.