Long-Term Effects of Paced Heart Rate on Central Blood Pressure in Patients with Sinus Node Dysfunction and...

Background and Objectives: Prior cardiac pacemaker studies examining the relationship between heart rate and central (aortic) blood pressure (BP) have predominantly used acute designs, limiting generalisability to long-term settings. The aim of this study was to assess the long-term effects of two clinically realistic pacing rate strategies on the central BP profile in permanently paced sinus node dysfunction (SND) patients in sinus rhythm and on antihypertensive medication. Materials and Methods: In this prospective, single-centre, randomised, single-blind, exploratory crossover clinical trial, the study participants completed two eight-week intervention periods (DDD 55 and 75 bpm) separated by a two-week washout. Office peripheral and central haemodynamics were measured at baseline and at the end of each period non-invasively with an oscillometric cuff-based device (SphygmoCor XCEL). Results: The study included 22 subjects (median age 76 (IQR 73-78) years, 16 women). At DDD 55 bpm, central systolic BP (primary outcome) was higher than at DDD 75 bpm (mean 127.8 ± 13.4 and 121.3 ± 10.6 mmHg, respectively, p = 0.04), whereas systolic BP amplification (peripheral systolic BP-central systolic BP) and pulse pressure (PP) amplification (peripheral PP/central PP) were lower (systolic BP amplification: mean 8.5 ± 3.2 and 10.1 ± 2.9 mmHg, respectively, p = 0.02; PP amplification: mean 1.2 ± 0.1 and 1.3 ± 0.1, respectively, p < 0.01). Conclusions: Long-term pacing at a moderately accelerated physiological rate may be associated with lower central systolic BP compared with pacing at a slightly bradycardic rate, in older permanently paced SND patients with hypertension.