Arterial rigidity and cardiovascular vagosympathetic activity in normotensive and hypertensive obese and type 2 diabetic patients

An increase in arterial rigidity is associated with a poor cardiovascular p rognosis. Several studies have suggested that an increase in sympathetic ac tivity may be involved in essential hypertension. We have recently shown th at vagal control of heart rate (HR) variations during standardised tests is altered in normotensive obese and diabetic patients. The aim of the presen t study was to compare cardiovascular vagosympathetic activity in obese and type 2 diabetic patients, either normotensive or hypertensive, and to inve stigate the relationship between pulse pressure (an index of arterial rigid ity) and sympathetic activity in this population. Seventy normotensive obes e and 32 mildly hypertensive obese patients, 18 normotensive type 2 diabeti c patients and 14 mildly hypertensive type 2 diabetic patients were compare d With 21 control subjects. Finapres studied HR and blood pressure variatio ns. In the four groups, during a 6-min period at a controlled breathing rat e, the high frequency peak of HR variations was significantly reduced (p<0. 001). The mid-frequency peak of systolic BP variations in the standing posi tion. which depends on sympathetic activity, did not differ significantly b etween the four groups and control subjects. In obese and diabetic hyperten sive patients, this peak correlated significantly with pulse pressure measu red in the lying position (r=0.379; p=0.043 and r=0.81 : p<0.0001, respecti vely). This study 1. confirms that vagal control of HR variations is reduce d to a similar extent in obese and diabetic patients; and 2. suggests that cardiovascular sympathetic activity is relatively increased in these patien ts without significant difference between normotensive and hypertensive pat ients, but interestingly that the increase in arterial rigidity is associat ed with a higher sympathetic activity.