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Left ventricular hypertrophy in hypertension is associated with the insulin resistance metabolic syndrome
L Lind1, P E Andersson, B Andrén
1Department of Internal Medicine, University Hospital, Uppsala, Sweden.
Insights
Left ventricular hypertrophy is closely linked to insulin resistance, a key component of the metabolic syndrome. This study found decreased insulin sensitivity contributes to both hypertrophy and diastolic dysfunction in hypertensive patients.
Area of Science:
- Cardiology
- Metabolic Syndrome Research
- Hypertension Studies
Background:
- Insulin resistance syndrome is a cluster of metabolic abnormalities.
- Left ventricular hypertrophy (LVH) is a common complication of hypertension.
- The relationship between insulin resistance and LVH requires further investigation.
Purpose of the Study:
- To determine if left ventricular hypertrophy is associated with the insulin resistance syndrome.
- To explore the link between insulin sensitivity and cardiac structure/function in hypertensive individuals.
Main Methods:
- Fifty untreated hypertensive patients underwent 24-h ambulatory blood pressure monitoring.
- Echocardiography assessed left ventricular wall thickness and diastolic function.
- Hyperinsulinaemic euglycaemic clamp determined insulin sensitivity.
Main Results:
- Left ventricular wall thickness significantly correlated with fasting insulin levels and inversely with insulin sensitivity.
- Insulin sensitivity was the strongest predictor of left ventricular wall thickness, explaining 43% of variation.
- Diastolic dysfunction was also inversely related to insulin sensitivity.
Conclusions:
- Left ventricular hypertrophy is strongly associated with insulin resistance.
- Diastolic dysfunction is linked to decreased insulin sensitivity.
- These findings suggest LVH and diastolic dysfunction are associated with the insulin resistance metabolic syndrome.
Objective:
To investigate whether left ventricular hypertrophy is associated with the insulin resistance syndrome.
Methods:
Fifty patients with untreated hypertension were evaluated by recording office blood pressure during regular antihypertensive treatment and 24-h ambulatory blood pressure and office blood pressure after 4-6 weeks on placebo, echocardiography with M-mode measurements of left ventricular wall thickness and pulsed-wave Doppler measurements of mitral flow in diastole and the hyperinsulinaemic euglycaemic clamp, for determination of insulin sensitivity.
Results:
The left ventricular wall thickness was found to be significantly related to blood pressure [r = 0.44, P < 0.004 for 24-h ambulatory systolic blood pressure (SBP)], fasting insulin level (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). Multiple regression analysis with these relationships together with confounding factors age, sex, body mass index and waist: hip ratio as independent variables showed insulin sensitivity to be the only significant variable, explaining 43% of the variation in left ventricular wall thickness, whereas 24-h ambulatory SBP explained a further 7%. Left ventricular diastolic filling, as evaluated by the mitral Doppler early: atrial 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). However, multiple regression analysis showed that insulin sensitivity was 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 also related to a decreased insulin sensitivity, these findings suggest that left ventricular hypertrophy and diastolic dysfunction are associated with the insulin resistance metabolic syndrome.