Acoustic quantification: new diastolic indices of left ventricular function in hypertension correlation with Doppler echocardiography

Abstract

A study of left ventricular diastolic function in early hypertension was performed by the new method of acoustic quantification and Doppler echocardiography. A total of 23 untreated patients, five males and 18 females (mean age 53.52 +/- 9.10 years) with mild or moderate hypertension (160 +/- 13/98 +/- 10 mmHg) and 12 normal, age- and heart-rate-matched, control subjects were studied. All subjects showed normal left ventricular systolic function and wall thickness on two-dimensional echocardiography. The following indices were obtained. (1) Acoustic quantification (AQ): the time rate of area change in early diastole (dA/dt)E, in late diastole (dA/dt)A and their ratio (dA/dt)E/(dA/dt)A. (2) Doppler echocardiography: the early peak E, the late peak A flow velocities, their ratio E/A and deceleration E-F slope in early diastole. Measurements of left ventricular diastolic function by acoustic quantification showed, in the patient group, that the time rate of area change in early diastole (dA/dt)E was significantly lower (64.7 +/- 11.0 cm2/second versus 74.3 +/- 5.9 cm2/second; P < 0.01), the rate of area change in late diastole (dA/dt)A was not significantly higher (43.3 +/- 9.2 cm2/second versus 38.4 +/- 6.0 cm2/second; P > 0.05), and the ratio between the above indices (dA/dt)E/(dA/dt)A was significantly lower (1.55 +/- 0.42 versus 1.95 +/- 0.20; P < 0.01), compared with normal values. Doppler diastolic indices were all significantly abnormal in patients, in comparison with the values of the control group. Reduced left ventricular diastolic function was found in nine of 23 patients (39.1%) by the AQ method and eleven of 23 patients (47.8%) by Doppler echocardiography. Acoustic quantification was in agreement with Doppler echocardiography in identifying left ventricular diastolic dsyfunction in nine of 11 hypertensive patients with reduced Doppler diastolic values (82% sensitivity, 100% specificity). The correlation between the two methods showed that the time rate of area change in early diastole (dA/dt)E correlated well with the early peak E flow velocity (r = 0.59), the ratio between the time rates in early and late diastole (dA/dt)E/(dA/dt)A also correlated well with the Doppler E/A ratio (r = 0.89), while a poor correlation was found between the time rate of area change in late diastole (dA/dt)A and peak A flow velocity (r = 0.26). Thus abnormal diastolic filling of the left ventricle can be seen in the early stages of hypertension, even in the presence of normal systolic function and wall thickness, while acoustic quantification could be considered as a useful noninvasive modality for the early identification of left ventricular diastolic abnormalities.