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Dietary salt intake. A determinant of cardiac involvement in essential hypertension
R E Schmieder1, F H Messerli, G E Garavaglia
1Department of Internal Medicine, Ochsner Clinic, New Orleans, Louisiana 70121.
Insights
Dietary salt intake significantly impacts left ventricular hypertrophy in hypertension. Reducing salt may prevent or lessen cardiac structural changes in hypertensive patients.
Area of Science:
- Cardiology
- Hypertension Research
- Cardiac Physiology
Background:
- Left ventricular hypertrophy (LVH) is a maladaptive cardiac response to increased afterload in hypertension.
- The specific factors influencing LVH development in mild essential hypertension require further elucidation.
Purpose of the Study:
- To investigate clinical, hemodynamic, and endocrine factors modulating left ventricular structural adaptation in mild essential hypertension (WHO stages I-II).
- To identify key determinants of left ventricular hypertrophy in patients with essential hypertension.
Main Methods:
- Cross-sectional study evaluating patients with mild essential hypertension.
- Assessment of dietary salt intake via 24-hour urinary sodium excretion.
- Analysis of clinical (e.g., body mass index), hemodynamic (e.g., diastolic pressure), and endocrine (e.g., epinephrine) variables.
- Stepwise multiple regression analysis to determine independent predictors of left ventricular structure.
Main Results:
- Dietary salt intake, measured by sodium excretion, was a potent determinant of posterior wall thickness (r=0.64), relative wall thickness (r=0.67), and left ventricular mass (r=0.37).
- Diastolic pressure, BMI, hematocrit, and epinephrine showed weaker associations with left ventricular structure (r=0.31-0.40).
- Sodium excretion emerged as the strongest independent predictor for posterior and relative wall thickness.
Conclusions:
- Dietary salt intake is a critical determinant of cardiac structural adaptation in response to sustained increased arterial pressure.
- High salt consumption may exacerbate left ventricular hypertrophy, while salt restriction could mitigate its development in essential hypertension.
Abstract:
Because a given increase in afterload does not consistently produce the same degree of left ventricular hypertrophy, we evaluated several clinical, hemodynamic, and endocrine factors that are prone to modify the adaptation of left ventricular structure in patients with mild essential hypertension (World Health Organization stages I or II). Dietary salt intake assessed by sodium excretion over 24 hours was a powerful determinant of posterior wall thickness (r = 0.64, p less than 0.001), relative wall thickness (r = 0.67, p less than 0.001), and left ventricular mass (r = 0.37, p less than 0.05). In contrast, diastolic pressure, body mass index, hematocrit, and epinephrine were found to be weaker determinants of left ventricular structure (r = 0.31-0.40, p less than 0.05). A stepwise multiple regression analysis revealed that sodium excretion was the strongest predictor for posterior wall thickness (p less than 0.02) and relative wall thickness (p less than 0.05) independent of the other examined variables. These results identify dietary salt intake as a strong determinant of cardiac structural adaptation to a persistent increase in arterial pressure. Consequently, a high salt intake might aggravate and, conversely, dietary salt restriction might prevent (or at least mitigate) the development of left ventricular hypertrophy in patients with essential hypertension.