Evaluation of Left Ventricular Diastolic Function Using New Doppler Time Index

ABSTRACT

BACKGROUND: There is a clinical need for a simpler measurement of global cardiac function incorporating elements of both systole and diastole. Doppler time index is theoretically regarded as a sensitive index of global left ventricular perfomance and defined as the sum of isovolumetric contraction time (IVCT) and isovolumetric relaxation time (IVRT) divided by ejection time (ET). This study was designed to determine the clinical usefulness of the Doppler time index in patients with left ventricular diastolic dysfunction as well as systolic dysfunction. METHODS: The study population consisted of 23 patients with hypertension as a diastolic dysfunction group, 16 patients with low ejection fraction as a systolic dysfunction group and 31 subjects with normal LV function. The ejection fraction (EF) was measured using M-mode echocardiography. Doppler profiles such as IVCT, IVRT and ET were obtained from Doppler echocardiography. The Doppler time index [ (IVCT+RT)/ET] was calculated from each Doppler velocity profiles. RESULTS: IVRT, IVRT/ET and (IVCT+VRT)/ET were significantly increased in the diastolic dysfunction group (120.5+/-19.5 msec, 0.45+/-0.1, 0.64+/-0.2, respectivelyp<0.001, p<0.001, p<0.001, respectively) compared with normal subjects (66.1+/-17.4 msec, 0.25+/-0.0, 0.41+/-0.1). IVCT and IVRT were significantly increased and ET was significantly shortened in systolic dysfunction group (75.4+/-25.7, 144.0+/-39.5 msec, 242.7+/-46.5 msec respectivelyp<0.001, p<0.05, p<0.05, respectively) compared with diastolic dysfunction group (50.4+/-23.0 msec, 120.5+/-19.5 msec, 276.8+/-44.6 msec, respectively). IVCT/ET, IVRT/ET and (IVCT+IVRT)/ET also were increased in patients with systolic dysfunction group (0.32+/-0.1, 0.61+/-0.2, 0.93+/-0.2 respectivelyp<0.01, p<0.01, p<0.001, res-pectively) compared with diastolic dysfunction group (0.19+/-0.1, 0.45+/-0.1, 0.64+/-0.2). Ejection fraction calculated by M-mode parameters was significantly correlated with (IVCT+IVRT)/ET (correlation coefficient - 0.605, p<0.001). CONCLUSION: The Doppler time index was significantly difficient from normal subjects in patients with isolated LV diastolic dysfunction as well as in those with systolic dysfunction. Thus, this index can be used as a sensitive indicator of myocardial performance.