[Relationship between blood pressure, heart rate and cardiac autonomic dysfunction in non-diabetic obese patients]

Some studies suggest that a high heart rate (HR) would be predictive of the incidence of an elevated blood pressure (BP). Cardiac autonomic dysfunction (CAD) affects a high proportion of obese patients. CAD could be involved in BP increase. Our aim was to examine the relationship between CAD, HR and BP in obese patients without known diabetes.We included 428 overweight or obese patients. CAD was assessed by analyzing HR variations during three standard tests (Valsalva, deep breathing, lying-to-standing), which are mostly dependent on vagal control. An oral load in glucose was performed and the Matsuda index was calculated.The population was separated in 4 groups according to the grade of CAD (no or only one abnormal test, 2 or 3 abnormal tests) and HR (or ≥ 75 bpm). Age was similar in the four groups. Systolic (P=0.05), diastolic (P0.005) and mean BP (P0.001) differed significantly between the 4 groups, and was the highest in the group of patients who had 2 or 3 abnormal tests and HR ≥ 75 bpm. Matsuda index differed across the groups (P=0.018) and was the lowest in this group.These data indicate that among overweight or obese patients with a defect in cardiac vagal activity BP is elevated only in those with a high heart rate, which is indicative of a more marked insulin resistance and probably an excess in sympathetic activity.