Dissipative energy loss within the left ventricle detected by vector flow mapping in dilated cardiomyopathy patients

Objective To quantitatively analyze the energy loss (EL) of the left ventricle in dilated cardiomyopathy (DCM) by vector flow mapping (VFM). Methods Sixty-four DCM patients confirmed by clinical were enrolled and divided into three groups according to the level of left ventricular ejection fraction (LVEF): mild decreased LVEF group(group A, 40%≤LVEF<50%), moderate decreased LVEF group(group B, 30%≤LVEF<40%) and severe decreased LVEF group ( group C, LVEF<30%). Forty healthy volunteers were selected as control group (group D, 53%≤LVEF≤73%) for physical examination. The images of apical four-chamber and three-chamber in color Doppler echocardiography were acquired and EL was analyzed in different phases in a cardiac cycle. Results There was no significant difference of the EL in isovolumic systole and isovolumic diastole between DCM groups and the control group (P>0.05). In rapid and slow ejection period, the EL in group B and C were much lower than those in the control group (P<0.05). In rapid filling phase, the EL in DCM groups were much lower than that in the control group (P<0.05). While in slow filling period and atrial systole the EL in group C was lower than that in the control group (P<0.05). Conclusions VFM provides a new perspective for the cardiac function study of DCM patients. Key words: Echocardiography; Cardiomyopathy, dilated; Ventricular function, left; Vector flow mapping; Energy loss