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[Determinants of the left ventricular mass in obese patients. Influence of lean body mass]
A Avignon1, G du Cailar, J Ribstein
1Service des maladies métaboliques, hôpital Lapeyronie, Montpellier.
Insights
Lean body mass, not insulin sensitivity, significantly predicts left ventricular mass (LVM) in obese women. Blood glucose also independently predicts LVM, highlighting the importance of body composition and metabolic factors in cardiac health.
Area of Science:
- Cardiology
- Obesity Medicine
- Metabolic Health
Background:
- Left ventricular mass (LVM) is influenced by systolic blood pressure and body mass index (BMI).
- Cardiac hypertrophy in obesity involves complex hemodynamic and metabolic factors.
- Morphologic features are known to correlate with LVM.
Purpose of the Study:
- To investigate the impact of morphologic and metabolic characteristics on LVM in obese women.
- To identify independent predictors of LVM in this population.
Main Methods:
- 2D echocardiography assessed LVM in 24 normotensive, normoglycemic obese women (BMI 27.5-52.2 Kg/m²).
- Bio-impedancemetry measured lean and fat body mass.
- Minimal model (Bergman) assessed insulin sensitivity (Si); indirect calorimetry measured basal metabolism.
Main Results:
- LVM positively correlated with BMI, waist-to-hip ratio, basal metabolism, lean body mass, and fat body mass.
- Fasting glycemia and triglyceride levels correlated positively with LVM.
- Lean body mass (r=0.74) and blood glucose were identified as significant, independent predictors of LVM via multivariate regression (multiple r=0.87).
Conclusions:
- Lean body mass is a key determinant of LVM in obese, normotensive individuals.
- Correcting LVM for lean body mass may offer greater accuracy in obese women than using body surface area or height.
- No relationship was found between LVM and insulin sensitivity; the link between blood glucose and LVM warrants further investigation.
Abstract:
Systolic blood pressure and body mass index (BMI) are the main determinants of the left ventricular mass (LVM). The mechanism of this cardiac hypertrophy in the obese individual is multifactorial and involves hemodynamic as well as metabolic factors. The association of LVM with the morphologic features of the individual are well known. The aim of this study was to assess the influence of the morphologic and metabolic features of obese women on LVM. 2D echocardiography evaluation of LVM was done in 24 normotensive, normoglycemic obese women (BMI [27.5-52.2 Kg/m2). Lean and fat body mass were determined by bio-impedancemetry, insulin sensitivity (Si) by the minimal model (Bergman), and basal metabolism by using indirect calorimetry. There was a positive correlation between LVM and BMI (r = 0.61; p = 0.001), waist to hip ratio (r = 0.45; p = 0.03), basal metabolism (r = 0.61, p = 0.001), lean (r = 0.74, p = 0.0002) and fat (r = 0.49; p = 0.01) body mass. Fasting glycemia was positively correlated with LVM (r = 0.62; p = 0.001), but not Si. LVM was also positively correlated to the triglyceride level. No relations were found with systolic or diastolic blood pressure. Multivariate regression analysis was performed to determine the relative contribution of lean body mass (the morphologic variable with the best association to LVM in univariate analysis), blood glucose, waist to hip ratio, age and triglycerides. The multiple r for the model was 0.87 (p < 0.001). Lean body mass and blood glucose were found to be the only significant and independent predictors of LVM (p = 0.001 and p = 0.03 respectively). We conclude that: 1) lean body mass is an important determinant of LVM in obese normotensive individuals. Hence, in obese women, correcting LVM for lean body mass might be more accurate than correcting it for body surface area or height. 2) There is no relationship between LVM and insulin sensitivity. The link between blood glucose and LVM needs to be studied further.