Speed of Heart Rate Recovery in Response to Orthostatic Challenge

Cathal McCrory, Lisa F. Berkman, Hugh Nolan, Neil O’Leary, Margaret Foley, Rose Anne Kenny

Speed of Heart Rate Recovery (HRR) may serve as an important biomarker of aging and mortality. To examine whether the speed of HRR following an orthostatic maneuver (i.e. active stand from supine position) predicts mortality. A longitudinal cohort study involving a nationally representative sample of community dwelling older persons aged 50 years+. 4475 participants completed an active stand at baseline as part of a detailed clinic-based cardiovascular assessment. Beat-to-beat heart rate and blood pressure responses to standing were measured over a two-minute window using a finometer and binned in 10-second intervals. We modeled HRR to the stand by age group, cardiovascular disease burden, and mortality status using a random effects model. Mortality status over a mean follow-up duration of 4 years served as the primary end-point (n=138). Speed of HRR in the immediate 20 seconds after standing was a strong predictor of mortality. A one beat per minute slower between 10 and 20 seconds after standing increased the hazard of mortality by 6% controlling for established risk factors. A clear dose-response relationship was evident. 69 participants in the slowest HRR quartile died over the observation period compared with 14 participants in the fastest HRR quartile. Participants in the slowest recovery quartile were 2.3 times more likely to die compared with those in the fastest recovery quartile. Speed of orthostatic HRR predicts mortality and may aid clinical decision making. Attenuated orthostatic HRR may reflect dysregulation of the parasympathetic branch of the autonomic nervous system.