Quantitative Analysis of Contribution of Rate Response in Three Different Ventricular Rate Responsive Pacemakers During Out of Hospital Activity

Abstract

The contribution of rate response provided by three different types of rate responsive pacemaker (Sensolog, Meta, and Vitatron TX) was assessed in 25 patients during out of hospital activity. Pacemakers were optimally programmed and full disclosure 24-hour Holter ECG recordings were obtained during everyday activities. Close visual analysis of these tracings revealed that rate response is active for less than 15% of the 24-hour study period with high rate response (paced rate above 100 beats/min) for just 5% of the day showing peak activation between 1600 and 2000 hours. Low rate response (paced rate below 100 beats/min but 5 beats above base rate) was maximal between 0800 hours and midday and comprised 10% of all heart beats during the study period. Thirty percent of study patients were nonpacemaker dependent and rate response in these subjects was significantly (P less than 0.001) less active between 0800 hours and midday than in pacemaker dependent patients though it was equivalent at all other times. Nonpacemaker dependent patients achieved natural sinus response in the morning and tended to rely on pacemaker supplied rate response in the latter part of the day.

Individual Optimization of Pacing Sensors Improves Exercise Capacity without Influencing Quality of Life

“…To date, limited studies investigated the effect of sensor adjustment and to the best of our knowledge; our study is the first and largest randomized controlled study, comparing DSS with OSS in detail. Previous studies mainly compared different sensors and were not primarily designed to evaluate individual adjustment 5,8,13–16,20 . Sulke et al showed that appropriate programming of sensors is crucial in rate responsive pacing 8 .…”

“…These methods, together with evaluation of the obtained quality of life (QOL), associated with a given sensor can all be used to assess the efficacy of a pacemaker sensor. The American college of cardiology guidelines of exercise testing used for evaluating rate response pacing advices adjustment of the exercise test for the subject's need and however several exercise tests (CAEP, LITE, Bruce, 6‐minute walk test, Kaltenbach step test, stair climbing) are described, consensus lacks about the ideal exercise test protocol for pacemaker sensor optimization 8–16 …”