Improvement of Exercise Tolerance Capacity by Use of Activity-Sensing Rate Responsive Pacemaker

The Activity-Sensing Rate-Responsive Pacemaker (RR-PM) varies the pacing rate in response to the level of physical activity.The effect of RR-PM was compared with that of conventional fixed-rate pacing (VVI-PM) on symptoms and exercise capacity (peak oxygen consumption and anaerobic threshold) during treadmill exercise in 6 patients between the ages of 38 and 75 years with complete atrioventricular block. A newly programmed treadmill exercise protocol was used for the measurement of anaerobic threshold.In the Rate-Responsive (RR) mode, the heart rate increased from 61±4 beats/min (bpm) to 103±12 bpm during maximal exercise ; the peak oxygen consumption and oxygen consumption at the anaerobic threshold significantly increased to a greater extent in RR mode than it did in fixed rate pacing mode. Thus, the use of RR-PM leads to better exercise tolerance than VVI-PM in complete atrioventricular block patients.