INFLUENCE OF RESTING HEART RATE ON BLOOD PRESSURE LOWERING EFFECT

Abstract

Objective: Elevated resting heart rate (RHR) identifies hypertensive subjects at higher cardiovascular risk. The study was aimed to compare benefit of intensive blood pressure (BP) lowering in subjects with higher and lower RHR. Design and method: The analysis was performed using Systolic Blood Pressure Intervention Trial (SPRINT) data shared by National Heart, Lung and Blood Institute. SPRINT trial assessed intensive lowering of systolic BP to a target < 120 mm Hg in comparison to standard goal (< 140 mm Hg). Baseline RHR was estimated as a pulse rate obtained during automated office BP measurements at first study visit. RHR higher than 80 b.p.m. was defined as increased according to current European Society of Cardiology guidelines. Composite outcome event (CE) included myocardial infarction and other acute coronary syndrome, stroke, heart failure decompensation and cardiovascular death. Cox proportional model was used to assess impact of BP lowering in subjects with RHR higher and lower than 80 bpm. P-value for interaction between study BP intervention and baseline RHR. Results: Data of 9361 SPRINT participants, aged 67.9 ± 9.4 years, were analyzed. 3332 (35.6%) were female an 1877 (20.1%) were diagnosed with prior cardiovascular disease. Mean baseline RHR was 66.3 ± 11.6 b.p.m. Baseline HR in both treatment arms was similar (standard arm 66.3 ± 11.7 b.p.m. vs intensive arm 66.2 ± 11.5 b.p.m., p = 0.762) 1198 (12.8%) participants had baseline RHR higher than 80 b.p.m. and experienced 78 (6.8%) CE events. There were 484 (5.9%) events among subjects with RHR lower than 80 b.p.m. Intensive lowering of systolic BP was beneficial both in subjects with elevated RHR (hazard ratio 0.79 with 95% confidence interval 0.51–1.24, p = 0.311) and non-elevated RHR (hazard ratio 0.75 with 95% CI 0.62–0.89, p = 0.002). The intervention between study BP intervention and baseline RHR was not significant (p for interaction 0.819). Conclusions: Elevated RHR does not influence effect of BP reduction on cardiovascular events risk.