Heart Rate Variability and Baroreflex Sensitivity in Hypertensive Subjects With and Without Metabolic Features of Insulin Resistance Syndrome

• Published in: American journal of hypertension 1998-05, Vol.11 (5), p.523-531
• Main Authors: Pikkujämsä, Sirkku M, Huikuri, Heikki V, Airaksinen, K.E.Juhani, Rantala, Asko O, Kauma, Heikki, Lilja, Mauno, Savolainen, Markku J, Kesäniemi, Y.Antero
• Format: Article
• Language: English
• Subjects: Adult; Arterial hypertension. Arterial hypotension; autonomic nervous system; Baroreflex - physiology; baroreflex sensitivity; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; Female; Heart Rate - physiology; Heart rate variability; Humans; hypertension; Hypertension - physiopathology; Insulin Resistance; Male; Medical sciences; Middle Aged; Reference Values; Regression Analysis; Syndrome
• ISSN: 0895-7061; 1879-1905; 1941-7225
• DOI: 10.1016/S0895-7061(98)00035-1

Both abnormal autonomic control of heart rate, assessed by heart rate variability (HRV) and baroreflex sensitivity (BRS), and insulin resistance syndrome are common in hypertensive patients. It is not known, however, whether abnormalities in HRV and BRS in hypertension are related to the insulin-resistance syndrome. Therefore, we compared HRV and BRS in hypertensive subjects with and without metabolic features of the insulin-resistance syndrome. HRV was analyzed using the autoregressive method from a 45-min electrocardiographic recording (15 min lying, sitting, and standing) and BRS using the Valsalva maneuver. The groups were matched for age, sex, and antihypertensive medication, and age- and sex-matched normotensive subjects served as a control group (n = 69 in each group). The insulin-resistance syndrome was defined using the criteria of 1) hypertension (blood pressure >160/90 mm Hg), 2) hypertriglyceridemia (fasting serum triglycerides ≥2.0 mmol/L), and 3) hyperinsulinemia (fasting serum insulin ≥12 mU/L). Standard deviation of RR intervals, total, very-low-, and low-frequency power of HRV were significantly lower in hypertensive subjects with insulin-resistance syndrome compared to hypertensive subjects without the syndrome and to normotensive controls ( P < .001 for all), but the hypertensive group without the syndrome did not differ from the normotensive group. High-frequency power of HRV ( P