A PROSPECTIVE RANDOMIZED COMPARISON BETWEEN FIXED RATE RESPONSE PROGRAMMING AND AUTOMATIC RATE RESPONSE OPTIMIZATION IN ACTIVITY-TRIGGERED DDDR PACEMAKERS

Activity rate response programming depends on the physician's experien ce and on the limited knowledge of patient's daily activities. The pre sent investigation compares a new continuous automatic adjustment of t he activity rate response called rate response optimization (OPT) with fixed activity rate response programming (FIXED). At hospital dischar ge 37 patients with Thera DR pacemakers (Medtronic) were randomized ei ther to FIXED (n = 20; 65 +/- 12 years, male n = 12) or to OPT (n = 17 ; 65 +/- 12 years, male n = 13). After 1 month's follow-up occurrence of complaints related to rate-responsive pacing and the percentage of pacing were assessed. Other activity sensor parameters were programmed according to clinical judgement and similarly distributed in the two groups. Activity rate response was 7.1 +/- 1.4 (FIXED) and 7.2 +/- 1.7 (OPT), activity threshold was medium in 9 (FIXED) and 8 (OPT), and me dium/low in II (FIXED) and 9 (OPT) patients, respectively. No patient with FIXED had any complaints with respect to activity-triggered rate response. One patient with OPT reported palpitations due to rapid chan ges in the pacing rate leading to reprogramming of the pacemaker. Atri um and ventricle were paced in 56 +/- 31% (FIXED) and in 58 +/- 35% (O PT; not significant) and the atrium only in 4 +/- 10% (FIXED) and 0% ( OPT; not significant), respectively. In the 17 patients programmed to OPT the pacemaker increased activity rate response in 5 and decreased activity rate response in 3 patients. In conclusion, as only 1 (3%) pa tient had complaints related to the activity rate response and fixed r ate response programming according to clinical judgement already resul ting in symptom-free DDDR pacing, no differences could be detected bet ween the fixed rate response programming and rate response optimizatio n.