Atrioventricular Conduction in the Hypertensive Patient: Influence of Aging, Pulse Pressure, and Arterial Stiffness

Abstract

Atrioventricular (AV) conduction time (PR interval) lengthens with age. Hypertension is often presented as an accelerated aging of the heart and arteries. The principal marker of arterial aging is an increase in arterial stiffness and pulse pressure. We were interested to find out whether parameters of blood pressure and arterial stiffness were related to the PR interval and whether they influenced its long-term progression. We examined factors linked to the PR interval at baseline in a cohort of untreated hypertensive patients including office and 24-hr blood pressure and arterial stiffness (QKD(100-60)). Long-term evolution of the PR interval and related factors were obtained during follow-up of this population. Baseline data were obtained in 1,034 untreated hypertensive patients. At baseline, four variables emerged as significantly and independently correlated with PR interval: Gender, age, weight, and heart rate. During follow-up (137 ± 78 months), 328 of these patients were re-examined. In this group, PR increased from 159 ± 20 to 167 ± 25 msec (p<0.001), a mean alteration of 8 ± 19 msec. This change was correlated with the baseline 24 hr PP (r=0.17, p=0.004) and with the duration of follow-up (r=0.13, p=0.02). In the group with baseline evaluation of arterial stiffness (n=141), QKD(100-60) was correlated with the change in PR interval (r= -0.33, p<0.0001) along with the duration of follow-up (r=0.22, p=0.005). This study shows a link between baseline increased pulse pressure or arterial stiffness with the prolongation of the PR interval with aging. Because this link was observed during follow-up, it is possible that increased arterial stiffness favors the increase in the PR interval with age.