INITIAL CLINICAL-EXPERIENCE WITH RATE ADAPTIVE CARDIAC PACING USING 2 SENSORS SIMULTANEOUSLY

In the rate adaptive pacemakers, all presently available sensors show one or more drawbacks. Combining two sensors in a single pacemaker, we tried to optimize its rate responsive characteristics. In this study, we present the rate adaptive behavior of a two sensor pacemaker system, using both QT interval and activity sensing. In addition, we compared the rate response with that of each sensor alone. Nine patients with an implanted QT interval sensing pacemaker, and an externally attached activity sensing pacemaker performed three exercise stress tests on treadmill. The QT interval, measured by the implanted pacemaker, and the activity level, were transmitted to an external computer. This computer contained the two sensor rate adaptive algorithm, reprogrammed the implanted pacemaker on beat-to-beat basis. Conclusion: In the two sensor mode the rate increases immediately at the onset of exercise, caused by the prompt response of the activity sensor. Furthermore, the rate decay during the recovery phase is more physiological.