LEFT-VENTRICULAR HYPERTROPHY IN HYPERTENSION IS ASSOCIATED WITH THE INSULIN-RESISTANCE METABOLIC SYNDROME

Objective: To investigate whether left ventricular hypertrophy is asso ciated with the insulin resistance syndrome. Methods: Fifty patients w ith untreated hypertension were evaluated by recording office blood pr essure during regular antihypertensive treatment and 24-h ambulatory b lood pressure and office blood pressure after 4-6 weeks on placebo, ec hocardiography with M-mode measurements of left ventricular wall thick ness and pulsed-wave Doppler measurements of mitral flow in diastole a nd the hyperinsulinaemic euglycaemic clamp, for determination of insul in sensitivity. Results: The left ventricular wall thickness was found to be significantly related to blood pressure [r = 0.44, P < 0.004 fo r 24-h ambulatory systolic blood pressure (SBP)], fasting insulin leve l (r = 0.32, P < 0.03) and haematocrit level (r = 0.37, P < 0.009) and inversely related to insulin sensitivity (r = -0.59, P < 0.0001). Mul tiple regression analysis with these relationships together with confo unding factors age, sex, body mass index and waist:hip ratio as indepe ndent variables showed insulin sensitivity to be the only significant variable, explaining 43% of the variation in left ventricular wall thi ckness, whereas 24-h ambulatory SBP explained a further 7%. Left ventr icular diastolic filling, as evaluated by the mitral Doppler early: at rial ratio, was significantly correlated with insulin sensitivity (r = 0.42, P < 0.003) and inversely related to blood pressure (r = -0.41, P<0.02 for 24-h ambulatory SBP), left ventricular wall thickness r = - 0.34, P < 0.02) and serum fibrinogen level (r = -0.63, P < 0.0001). Ho wever, multiple regression analysis showed that insulin sensitivity wa s more closely related to diastolic filling than to blood pressure or left ventricular wall thickness. Conclusion: The present study showed left ventricular wall thickness to be closely associated with insulin resistance. Because diastolic dysfunction of the left ventricle was al so related to a decreased insulin sensitivity, these findings suggest that left ventricular hypertrophy and diastolic dysfunction are associ ated with the insulin resistance metabolic syndrome.