Diastolic Cardiac Function in Hypertension

Lee, Yung; Hong, Kyung Pyo

Abstract

We measure left ventricular mass, mitral peak flow velocity and isovolumic relaxation time(IVRT) with M-mode and Doppler echocardiography to evaluate daistolic function of the heart in hypertensive patients, who are seperated into group A(18 patients) with normal electrocardiogram and group B(24 patients) with abnormal electrocardiogram. There is no difference in fractional shortening, which reflects systolic function of the heart,between normal subjects and both groups of patients(36.5+/-6.7% in group B).The left ventricular mass index in group A is higher than in normal subjects(139.8+/-33.6g/m2, 100.2+/-28.8g/m2, respectively, p<0.005). But, that is lower than group B(200.7+/-40.6g/m2, p<0.005). The sensitivity and specificity of electrocardiograohy to detect left ventricular hypertrophy in patient whose left ventricualr mass index is above 160.8g/m2, are 80% and 91%, respectively. The peak flow velocities in early diastolic(PFVE) are 0.67+/-0.15m/sec in normal subjects and 0.60+0.14m/sec in group A (p=not siginificant). In group B, that is lower than normal subjects(0.54+/-0.15m/sec, p<0.005). In both groups, the peak flow velocities in late diastole(PFVA) are higher than normal subjects(0.48+/-0.11m/sec in normal, 0.69+/-0.18m/sec in groups A, 0.71+/-0.16m/sec in group B, p<0.005). The PFVE/PFVA ratio is lower in both groups of patients(1.40+/-0.23 in normal subjects, 0.90+/-0.25 in group A, 0.77+/-0.23 in group B, p<0.005). The IVRT is also prolonged in both groups(85+/-10m/sec in normal, 112+/-16msec in group A, 123+/-23msec in group B, p<0.005). The PFVE/PFVA ratio decreases in relation with the increament of index of IVRT(r=0.60, p<0.01). The IVRT increases in relation to the left ventricular mass index in hypertensive patients(r=0.34, p<0.05), but, the PFVE/PFVA ratio reveals no relation to those. In cocclusion, the impairment of diastolic function develops before the systolic function or electrocardiogram show abnormalities in htpertensive patients.Therefore, it is importment to detect early any abnormalities in the indices of the diastolic function, such as mitral peak flow velocity and isovolumic relaxation time, in the prevention and treatment of hypertensive geart disease.