Chronotropic response during treadmill exercise and subclinical carotid atherosclerosis after adjusting for the calibrated SCORE risk classification: a cross-sectional study.

Carotid atherosclerosis (CA) and chronotropic incompetence (CI) during exercise are two independent cardiovascular risk factors. Aim of the current study was to investigate the possible association between them, in apparently healthy individuals, after adjusting for the 10-year cardiovascular disease (CVD) risk score. This cross-sectional study consisted of 139 apparently healthy subjects, 40-65 years old, who underwent treadmill exercise test (Bruce protocol used), which showed no evidence of ischemia. Heart rate reserve (HR reserve) was calculated to assess chronotropic response; a value of ≤ 0.80 is considered CI. CA was assessed by the presence of carotid plaque(s) in common and internal carotid arteries and carotid bulb bilaterally, using B-mode ultrasound. A calibrated version of SCORE (i.e., HellenicSCORE) was used to estimate the 10-year fatal CVD risk; participants were classified into low-, moderate- or high-risk group. CI was present in 7.9 % and CA in 18.7 % of the participants. After adjusting for 10-year CVD risk and other key confounders, odds of CA were 8.6 times higher in subjects with CI compared to their counterparts with normal chronotropic response to exercise. The results of the study indicate that CI during exercise can lead to high clinical suspicion of CA in apparently healthy individuals.