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Relationship between left ventricular wall thickness and left atrial size: comparison with other measures of
C L Simek1, M D Feldman, H L Haber
1Cardiovascular Division, University of Virginia, Charlottesville 22908, USA.
Insights
Left atrial size, measured via echocardiography, better reflects long-term hypertension effects on the heart than traditional measures. This simple assessment can indicate the severity of left ventricular diastolic dysfunction in hypertensive patients.
Area of Science:
- Cardiology
- Echocardiography
- Hypertension Research
Background:
- Essential hypertension can lead to cardiac structural changes, including left ventricular (LV) diastolic dysfunction.
- Traditional hemodynamic and Doppler measures may not fully capture the chronicity of hypertensive heart disease.
Purpose of the Study:
- To investigate if left atrial (LA) size correlates with LV wall thickness in essential hypertension patients with normal LV systolic function.
- To determine if LA size is a better indicator of chronic LA hypertension than conventional diastolic function measures.
Main Methods:
- 30 essential hypertension patients underwent hemodynamic, Doppler, and two-dimensional echocardiography.
- Measurements included LV wall thickness, LV ejection fraction, pulmonary capillary wedge pressure, LV end-diastolic pressure, isovolumic LV pressure relaxation, E/A ratio, and LA area.
Main Results:
- Hemodynamic and Doppler measures showed poor correlation with LV wall thickness (r = 0.01 to -0.52).
- LA area demonstrated a strong correlation with LV wall thickness (r = 0.77 to 0.86).
- LA area in atrial systole was the best correlate of LV wall thickness.
Conclusions:
- LA size, particularly in atrial systole, serves as a simple, noninvasive marker for assessing the chronicity and severity of left ventricular diastolic dysfunction in hypertension.
- LA size reflects long-term left atrial pressure changes, offering insights beyond standard functional assessments.
Abstract:
We postulated that in patients with essential hypertension and normal left ventricular (LV) systolic function, left atrial (LA) size correlates with LV wall thickness by better reflecting the chronicity and duration of LA hypertension than the commonly used hemodynamic and Doppler measures of LV diastolic function. Accordingly, hemodynamic, Doppler, and two-dimensional echocardiographic measurements were performed in 30 subjects with no cardiovascular abnormalities other than essential hypertension (mean systolic blood pressure of 150 +/- 29 mm Hg). The mean LV wall thickness was 0.57 +/- 0.14 cm/m2 and the mean LV ejection fraction was 0.62 +/- 0.12. Hemodynamic and Doppler measures including pulmonary capillary wedge and LV end-diastolic pressures, isovolumic LV pressure relaxation, LV chamber elastic stiffness, and E/A ratio (E and A waves on the pulsed Doppler signal of the mitral valve) correlated poorly (r = 0.01 to -0.52) with LV wall thickness. Both E/A ratio and isovolumic LV pressure relaxation correlated better (p = 0.05) with patient age than with LV wall thickness. In contrast, LA area (in the apical four-chamber view) had a good correlation (r = 0.77 for LA area in atrial diastole and r = 0.86 for LA area in atrial systole) with LV wall thickness. Multiple regression analysis revealed LA area in atrial systole to be the best correlate of LV wall thickness. We conclude that because the left atrium is a thin-walled structure, its size may increase with an increase in LA pressure. In the absence of mitral valve disease and atrial fibrillation, LA size may reflect the chronicity and duration and thus the history of LA hypertension. LA size in the apical four-chamber view may, therefore, provide a simple noninvasive assessment of the degree of LV diastolic dysfunction.