Influence of sex on the relation between heart rate and aortic stiffness.

BACKGROUND: Heart rate and aortic pulse wave velocity (PWV) are both cardiovascular risk factors. The aim of this study was to evaluate the influence of sex on the heart rate-PWV relationship in two populations of normotensive and hypertensive men and women. PATIENTS AND METHODS: In a first study, steady-state data describing the heart rate-PWV relationship were determined in 558 normotensive men, 308 normotensive women, 323 hypertensive men and 93 hypertensive women. In a second study, the changes in blood pressure and PWV under atrial pacing at 60, 80 and 100 beats/min were investigated in 15 men and 15 women who were either normotensive or hypertensive.
RESULTS: In women in study 1, 26.8% of PWV variance in normotensive patients and 15.4% of PWV variance in hypertensive patients was explained by a multiple regression including only age and systolic blood pressure as covariates. In men in study 1, 27% of PWV variance in normotensive patients and 28.5% of PWV variance in hypertensive patients was explained by a multiple regression including age, systolic blood pressure, weight, and also heart rate, as covariates. In study 2, atrial pacing in the overall population tended to decrease mean blood pressure (P = 0.05) and increase pulse pressure (P = 0.003), with no substantial change in PWV. However, when heart rate increased, PWV tended to decrease in women and to increase in men (interaction: P = 0.07).CONCLUSION Accelerated heart rate influences PWV in both normotensive and hypertensive men and, through this mechanism, could influence cardiovascular risk. However, heart rate does not influence PWV in women.