Echocardiographic diastolic ventricular abnormality in hypertensive heart disease: Atrial emptying index

To analyze changes in left ventricular diastolic properties in hypertensive heart disease, the atrial emptying index was used to assess the rapid phase of diastolic filling of the left ventricle. Ten normal subjects (Group 1), 11 hypertensive patients without evidence of cardiac involvement (Group 2) and 10 hypertensive patients with echocardiographic evidence of left ventricular hypertrophy (Group 3) were compared using M mode echocardiography and systemic hemodynamic data. Where as cardiac index (dye-dilution method) and rate of circumferential fiber shortening (echocardiogram) were normal in all three groups, there was a progressive increase in left atrial index (p <0.001, Group 1 versus Group 2 and versus Group 3) and a progressive decrease in the atrial emptying index (p <0.001, Group 1 versus Group 2 and versus Group 3). No correlation existed between the atrial emptying index and the left atrial index, mean arterial pressure or total peripheral resistance in any of the three groups. These data suggest that rapid filling of the left ventricle is reduced early in hypertension, even before electrocardiographic or systolic echocardiographic abnormalities are detectable. The atrial emptying index therefore appears to be an early indicator of abnormalities of left ventricular diastolic compliance in uncomplicated hypertension.     

Myocardial contractility and left ventricular function in obese patients with essential hypertension

Although the risk of developing congestive heart failure increases in parallel with the degree of obesity, load-dependent indexes of left ventricular function are found to be reduced in patients with morbid obesity only. We used the ratio of end-systolic wall stress to end-systolic volume index, which is load-independent, to assess myocardial contractility in 23 nonobese, 28 mildly obese and 26 moderately obese patients with mild to moderate essential hypertension. Although load-dependent indexes (i.e., ejection fraction, fractional fiber shortening and velocity of circumferential fiber shortening) were similar in the 3 groups, end-systolic wall stress to end-systolic volume index was lower in the moderately obese group (2.63 +/- 0.4, p less than 0.002) and even in the mildly obese group (2.88 +/- 0.8, p less than 0.05) than in the nonobese group (3.27 +/- 0.7). Further, there was a significant inverse relation between end-systolic wall stress to end-systolic volume index and body mass index (r = -0.34, p less than 0.005), diastolic diameter (r = -0.56, p less than 0.001) and left ventricular mass index (r = -0.55, p less than 0.001). Some obese patients have depressed myocardial contractility when compared with lean patients despite well-preserved pump function.     

Cardiac status in juvenile borderline hypertension

A prospective M-mode echocardiographic study was done to look for early cardiovascular changes in children prone to hypertension with blood pressures between the 75th and 95th percentiles for age. Average systolic/diastolic pressures in 27 children with borderline hypertension were 137/89 mm Hg compared to 110/68 mm Hg for the 26 controls. Echocardiographic measurements were normalized for comparison using two methods. The borderline hypertensive group mean values were significantly greater than controls for left ventricular wall thickness (p less than 0.05 for method 1; p less than 0.001 for method 2), left ventricular mass (p less than 0.001; p less than 0.005) and left ventricular wall thickness to radius ratio (p less than 0.001, both methods). Echocardiographic estimates of left ventricular function were lower in the hypertensive group. This study suggests that cardiac hypertrophy can be shown by noninvasive means in some children before arterial pressure becomes elevated. To assess the incidence and possible consequences of early target organ changes, more extensive clinical evaluation of borderline hypertension in children is recommended.     

Sex differences in cardiac adaptation to essential hypertension

Left ventricular functional and structural adaptations to mild essential hypertension were assessed by 2D-guided M-mode echocardiography in a population of premenopausal and postmenopausal women (n = 29) who were matched with the same number of men with regard to mean arterial pressure, age and race. Premenopausal women had a thinner posterial wall (P less than 0.05), a smaller left ventricular systolic and diastolic diameter, and a smaller left ventricular mass than men with the same level of arterial pressure. Left ventricular performance indices, ejection fraction, velocity of circumferential fibre shortening, and the ratio of the end-systolic wall stress to the end-systolic volume index (a load-insensitive contractility index) were higher in women than in men. These sex differences were most pronounced before the menopause and tended to disappear thereafter. We conclude that in the presence of the same level of arterial pressure, women have smaller left ventricular dimensions and enhanced ventricular performance compared with men. These differences in cardiac adaptations between the genders may account for the lower risk of cardiovascular morbidity and mortality in premenopausal women with essential hypertension.