OBJECTIVE - Elevated resting heart rate has been independently associated with cardiovascular and all-cause mortality. The pathophysiological mechanisms by which this increased risk occurs are unclear. We hypothesized that elevated resting heart rate will be associated with increased development of atherosclerosis, as assessed by the incidence and progression of coronary artery calcium (CAC).
METHODS - The Multi-Ethnic Study of Atherosclerosis is a prospective cohort study of participants free of clinical cardiovascular disease at entry. Among persons without CAC at baseline, the association between increasing clinical categories of heart rate (<60, 61-70, 71-80, >80bpm) and CAC incidence was assessed by relative risk regression after adjusting for covariates. Among those with detectable CAC at baseline, progression of CAC was assessed using multivariable robust linear regression.
RESULTS - Our study population consisted of 6004 individuals (62±10 years, 48% males). Among 3079 individuals with no detectable CAC at baseline, 20% (n=620) developed CAC. After adjusting for CVD risk factors, participants with a baseline resting heart rate >80bpm had an increased risk of incident CAC as compared to those with a resting heart rate <60 (relative risk=1.65, 95% CI=1.02, 2.66). Among persons with CAC present at baseline, participants with a baseline resting heart rate >80bpm had greater CAC score progression than those with a resting heart rate <60 (β=17.10; 95% CI=4.29, 29.85).
CONCLUSION - Elevated resting heart rate, a well-described predictor of cardiovascular mortality with unclear mechanism, is associated with increased incidence and progression of coronary atherosclerosis among individuals free of CVD at baseline.
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