Minute ventilation sensor-driven rate response as a part of cardiac resynchronization therapy optimization in older patients.

Abstract

Chronotropic incompetence (CI) is common among elderly cardiac resynchronization therapy pacemaker (CRT-P) patients on optimal medical therapy. This study aimed to evaluate the impact of optimized rate-adaptive pacing utilizing the minute ventilation (MV) sensor on exercise tolerance. In a prospective, multicenter study, older patients (median age 76years) with a guideline-based indication for CRT were evaluated following CRT-P implantation. If there was no documented CI, requiring clinically rate-responsive pacing, the device was programmed DDD at pre-discharge. At 1month, a 6-min walk test (6MWT) was conducted. If the maximum heart rate was < 100bpm or < 80% of the age-predicted maximum, the response was considered CI. Patients with CI were programmed with DDDR. At 3months post-implant, the 6MWT was repeated in the correct respective programming mode. In addition, heart rate score (HRSc, defined as the percentage of all sensed and paced atrial events in the single tallest 10bpm histogram bin) was assessed at 1 and 3months. CI was identified in 46/61 (75%) of patients without prior indication at enrollment. MV sensor-based DDDR mode increased heart rate in CI patients similarly to non-CI patients with intrinsically driven heart rates during 6MWT. Walking distance increased substantially with DDDR (349 ± 132m vs. 376 ± 128m at 1 and 3months, respectively, p < 0.05). Furthermore, DDDR reduced HRSc by 14% (absolute reduction, p < 0.001) in those with more severe CI, i.e., HRSc ≥ 70%. Exercise tolerance in older CRT-P patients can be further improved by the utilization of an MV sensor.