[Insulin resistance and alteration of cardiac vagal activity in obese patients].
We have previously shown that alterations of vagal control of heart rate variations are found in more than half of non diabetic obese subjects (Int J Obes 1995) and are associated with a more severe insulin resistance in noninsulin dependent diabetic patients (Metabolism 1998). The aim of this study was to examine whether parasympathetic alterations are also associated with a more severe insulin resistance in non diabetic obese subjects. 245 obese subjects (BMI = 34.2 +/- 0.4 kg/m2) aged 38.6 +/- 0.8 years, with a normal oral glucose tolerance test were included. Parasympathetic activity was evaluated by heart rate variations during three standardised tests: Valsalva, deep-breathing and active lying-to-standing, with age being taken into account. The Valsalva maneuver was abnormal in 17.5%, the deep-breathing test in 18% and the lying-to-standing test in 30.3% of the cases. One hundred and thirty subjects (52.1%) had at least one abnormal test. Compared with those with three normal tests, the obese subjects with parasympathetic alterations had very similar BMI and blood pressure, but significantly higher values of heart rate (75.5 +/- 1.4 vs 71.3 +/- 1.1 beats/min, p = 0.02), fasting blood glucose (5.0 +/- 0.1 vs 4.8 +/- 0.1 mmol/L, p = 0.03) and plasma insulin (98 +/- 6 vs 82 +/- 4 pmol/L, p = 0.03). In the whole series of obese subjects, heart rate variations during the deep-breathing and lying-to-standing tests correlated negatively with blood glucose (p = 0.001 and p = 0.03 respectively), and during the deep-breathing test they correlated negatively with the waist/hip ratio (p = 0.004). This data suggests that cardiac parasympathetic alterations should take part in the insulin-resistance syndrome and might account for the poor cardiovascular prognosis linked to this syndrome.
Valensi
P
P
Service d'endocrinologie-diabétologie-nutrition, hôpital Jean-Verdier, université Paris-Nord, Bondy.
Paries
J
J
Assad
N
N
Lormeau
B
B
Attali
J R
JR
D000328:Adult; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007333:Insulin Resistance; D009765:Obesity / Q000503:physiopathology*; D014630:Vagus Nerve / Q000502:physiology*