The influence of heart rate on coronary artery atherosclerosis

Abstract

Elevated "casual" heart rate (HR) has been found to be an independent predictor of coronary heart disease (CHD) in human beings. The current study provides data on the association between coronary artery atherosclerosis (CAA) and naturally occurring individual differences in the casual HRs of cynomolgus macaques (Macaca fascicularis). The data demonstrate that naturally occurring differences in casual HR are related to CAA (plaque area in mm) with high HR monkeys having lesions more than twice as extensive as those of low HR monkeys (high HR; n = 7, 159 beats/min: 0.76 mm2 +/- 0.21 SD; low HR; n = 8, 133 beats/min: 0.31 mm2 +/- 0.30; t = 3.01, p less than 0.01). The data show further that the distribution of individual differences in casual HR is consistent and stable over periods of at least 12 months. Importantly, the relationship between elevated casual HR and CAA was independent of the association between an index of HR "responsivity" to stress and CAA, found in the same monkeys. Similar to a recent finding in human beings, high casual HR also was associated with significantly lowered serum concentrations of high-density lipoprotein cholesterol; differences in CAA were, however, independent of the lipid difference. The CAA differences may depend instead on HR-induced differences in coronary blood flow between high and low HR monkeys. Subsequent work with beta-adrenergic blockade suggested that elevated casual HRs in monkeys are associated with sympathetic arousal.