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Sex-specific determinants of increased left ventricular mass in the Tecumseh Blood Pressure Study
Insights
Left ventricular hypertrophy (LVH) has different causes in young men and women. In men, it
Area of Science:
- Cardiology
- Physiology
- Public Health
Background:
- Left ventricular hypertrophy (LVH) is a known risk factor for cardiovascular events.
- Previous studies identified male sex, hypertension, obesity, and aortic stenosis as LVH determinants.
- This study investigated LV mass (LVM) in young, normotensive adults without valvular disease.
Purpose of the Study:
- Establish sex-specific normal values for LVM index (LVMI).
- Identify correlates of LVMI in young men and women.
- Understand early determinants of LVH before hypertension onset.
Main Methods:
- M-mode echocardiography was used to measure LVM.
- LVMI was calculated and analyzed.
- Sex-specific criteria for LVH were established using the 90th percentile.
Main Results:
- Men exhibited significantly higher average LVMI (102.9 g/m2) than women (88.2 g/m2).
- Sex-specific LVH criteria were defined: men > 125.4 g/m2, women > 110 g/m2.
- In men, LVH correlated with sympathetic nervous system activity, fasting insulin, and triglycerides, suggesting insulin resistance. In women, LVH correlated with higher body weight and obesity.
Conclusions:
- Determinants of increased LVMI differ between young men and women before hypertension.
- Early LVH in men may indicate hyperkinetic borderline hypertension linked to sympathetic activity and insulin resistance.
- Increased adiposity appears to be the primary factor associated with LVH in young women.
Background:
Left ventricular hypertrophy (LVH) defined by either ECG or echocardiographic criteria is a risk factor for cardiovascular morbidity and mortality. A number of determinants of LVH have been described in previous studies, principally male sex, hypertension, obesity, and aortic valvular stenosis. We examined the distribution of LV mass (LVM) in a population of 18- to 42-year-old normotensive men and women who were free of valvular heart disease to establish sex-specific normal values for LVM index (LVMI) and to determine the correlates of LVMI.
Methods And Results:
LVM was derived from measurements obtained by M-mode echocardiography. Average LVMI is significantly greater in men (102.9 +/- 0.7 g/m2) than women (88.2 +/- 0.7 g/m2). By defining LVH as an LVMI greater than the 90th percentile, we developed sex-specific criteria for LVH: men, > 125.4 g/m2; women, > 110 g/m2. We found that LVH in men is associated with indices of enhanced sympathetic nervous system reactivity and with elevated fasting insulin and triglyceride levels, which may be caused by insulin resistance. In women, LVH was associated with higher body weight and obesity.
Conclusions:
Before the onset of hypertension, increased LVMI appears to have different determinants in men and women. We suggest that early LVH in young men is a manifestation of hyperkinetic borderline hypertension, a state previously shown to be associated with increased sympathetic nervous system activity and insulin resistance. The hyperkinetic state is less prevalent in young women, in whom increased adiposity seems to be the predominant factor associated with LVH.