Relations between carotid artery distensibility and heart rate variability: The Cardiovascular Risk in Young Finns Study

ObjectiveReduction in carotid artery wall elasticity may interfere with baroreceptor function that could lead to low vagal tone. We studied at the population level the relations between carotid-artery-distensibility (Cdist) and vagal modulation of heart rate.Methods and resultsCdist was assessed with ultrasonic measurements of changes in carotid artery diameter during cardiac-cycle. Vagal tone was estimated with the heart rate variability (HRV) in 1872 healthy 24–39 year-old subjects. Cdist was significantly related with all HRV-components (always P < 0.0001). After adjustments with sex, age and heart rate, we found statistically significant correlation between Cdist and the high-frequency component (HF, estimate of vagal-tone) of HRV (P < 0.05). An inverse association between the number of cardiovascular risk-factors and vagal-tone was seen in subjects with less elastic arteries, but not in subjects with more elastic arteries (P for interaction = 0.01).ConclusionsThese data support the hypothesis that reduction in carotid artery wall elastic properties may lead to low vagal tone. Furthermore, carotid distensibility seemed to modify the relation between risk-factors and HRV. Increased cardiovascular risk associated with low vagal tone may partly be mediated via changes in carotid artery elastic properties.