Data from: Optimal cardiac resynchronization therapy pacing rate in non-ischemic heart failure patients: a randomized crossover pilot trial

Background: The optimal pacing rate during cardiac resynchronization
therapy (CRT) is unknown. Therefore, we investigated the impact of
changing basal pacing frequencies on autonomic nerve function,
cardiopulmonary exercise capacity and self-perceived quality of life
(QoL). Methods: Twelve CRT patients with non-ischemic heart failure (NYHA
class II–III) were enrolled in a randomized, double-blind, crossover
trial, in which the basal pacing rate was set at DDD-60 and DDD-80 for 3
months (DDD-R for 2 patients). At baseline, 3 months and 6 months, we
assessed sympathetic nerve activity by microneurography (MSNA), peak
oxygen consumption (pVO2), N-terminal pro-brain natriuretic peptide
(p-NT-proBNP), echocardiography and QoL. Results: DDD-80 pacing for 3
months increased the mean heart rate from 77.3 to 86.1 (p = 0.001) and
reduced sympathetic activity compared to DDD-60 (51±14 bursts/100 cardiac
cycles vs. 64±14 bursts/100 cardiac cycles, p<0.05). The mean pVO2
increased non-significantly from 15.6±6 mL/min/kg during DDD-60 to 16.7±6
mL/min/kg during DDD-80, and p-NT-proBNP remained unchanged. The QoL score
indicated that DDD-60 was better tolerated. Conclusion: In CRT patients
with non-ischemic heart failure, 3 months of DDD-80 pacing decreased
sympathetic outflow (burst incidence only) compared to DDD-60 pacing.
However, Qol scores were better during the lower pacing rate. Further and
larger scale investigations are indicated. Trial Registration:
ClinicalTrials.gov NCT02258061