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[Echocardiographic study of the left ventricular mass-dilatation ratio in hypertensive disease]
Insights
Hypertensive cardiomyopathy causes the heart to thicken, even with treatment. This hypertrophy helps maintain normal heart chamber size, preventing dilation and reducing heart strain.
Area of Science:
- Cardiology
- Hypertension Research
- Medical Imaging
Context:
- Hypertension significantly impacts cardiovascular health, particularly in African populations.
- Echocardiography is a key tool for assessing cardiac structure and function.
- Understanding hypertensive cardiomyopathy progression is crucial for effective management.
Purpose:
- To interpret echocardiograms of hypertensive African subjects to understand cardiac changes.
- To evaluate left ventricular performance and mass using specific echocardiographic parameters.
- To propose a new concept on the progression of hypertensive cardiomyopathy based on a novel 'R' ratio.
Summary:
- Echocardiograms of 52 hypertensive African subjects were analyzed, measuring dimensions and wall thickness.
- Left ventricular performance was assessed via ejection fraction and fractional shortening; a new 'R' ratio was calculated.
- Findings indicate hypertensive hearts undergo hypertrophy, even with normalized blood pressure, to maintain diastolic dimension and reduce wall stress, suggesting left ventricular dilatation as the hypertrophy stimulus.
Impact:
- Introduces a new concept for understanding hypertensive cardiomyopathy progression.
- Highlights that cardiac hypertrophy in hypertension is a compensatory mechanism.
- Suggests left ventricular dilatation, not blood pressure, is the primary stimulus for hypertrophy.
Abstract:
The object of this work is the exhaustive interpretation of 52 echocardiograms of hypertensive African subjects. The following parameters were measured on the echocardiogram: Dd (left ventricular end diastolic dimension), Ds (left ventricular end systolic dimension), DSd (interventricular end diastolic dimension), DEd (left ventricular posterior wall end diastolic thickness). Left ventricular performance was evaluated with the calculated Vcf, FR (fractional shortening) and EF (ejection fraction). A ratio "R" was estimated as he ratio of the left ventricular mass (MVG) measured with Bennett's formula: [(Dsd + DEd + Dd)3-Dd3] x 1,05] to the left ventricular end diastolic dimension. A carotid pulse and phonocardiogram were simultaneously recorded and systolic time intervals were measured and corrected for heart rate, using regression equations corresponding to African subjects. The analysis of the "R" ratio has led us to put forward a new concept of the progression of the hypertensive cardiomyopathy. It has been shown, in this study, that the hypertensive heart becomes hypertrophic, even under treatment and after return of blood pressure to normal. It appears that hypertrophy is a reaction tending to keep normal or almost normal the telediastolic left ventricular dimension and consequently to prevent left ventricular dilatation. This can be explained by the tendency of myocardial hypertrophy to reduce wall stress and oxygen consumption. The analysis of the correlation between MVG and Dd (good), TAM (mean arterial blood pressure) and Dd (poor) and TAM and MVG (nil) has les us to the conclusion that the stimulus to hypertrophy lies in the left ventricular dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)