To Evaluate Left Ventricular Dissipative Energy Loss By Vector Flow Mapping In Patients With Dilated Cardiomyopathy

Objectives: The aim of this study was to assess left ventricular blood fluid changes and dissipative energy loss (EL) at different phases of cardiac cycle using vector flow mapping (VFM) in patients with dilated cardiomyopathy (DCM), and to evaluate usefullness in the clinical application of left ventricular function.Methods: This study included 35 patients with dilated cardiomyopathy and 45 healthy controls. Conventional echocardiography was performed in two groups. Then collected left ventricular flow vector diagram using VFM. The series parameters,including vortex circulation, area, numbers of vortices and energy loss (EL) were measured VFM DSA-RS1 analysis software. Differences were compared between DCM patients and controls at different periods. Summarized evolution law of vortex and analyzed similarities and differences. In addition, correlationship between function parameters, vorex area, circulation and EL were separately compared.Results: ①The movement direction of the blood flow was irregular in patients with DCM. EL increased at points where size and direction of velocity vectors changed.And the distribution of vorticity was wide and relatively scattered. ②The vortex area,circulation, numbers of the vortices increased in DCM patients compared with controls, while vortex area and circulation in PO ～ P6 and P8 were statistically significant (P<0.05) , numbers of vortices were all higher in DCM patients than controls during different phases(P<0.05).③ The patients with DCM had higher global EL at different periods. And a significant difference was found between two groups(P<0.05). ④ There were differences in EL at base, mid, apex segment of LV between two groups during different phases(P<0.05). EL-base increased than those of normal controls at the P0～P8,(P<0.05),EL-mid were also higher with statistically significant differences at the PO～P7(P<0.05). Compared with controls,EL-apex during different phases also increased(all P<0.05).⑤In DCM group,EL had a good correlation with vortex circulation, area at the P1, P2, P4, P8(P<0.05). P3-EL had a positive correlation with vortex area (P<0.05). P5-EL also correlated with vortex area,circulation (P<0.05), and significant linear correlations were found between EL and circulation , the number of vortices at the P7(P<0.05). In controls, EL significantly correlated with vortex circulation, area at P0, P1,P2, P8(P<0.05). EL had a positive correlation with the number of vortices at the P3, P6 (P<0.05).⑥In normal group,PO-EL had a good correlation with a, E/e, E, A (P<0.05); and there were also the positive correlationship between EL and E、E/A, e, e/a , E/e at the P1, P2(P<0.05);Positive correlation between P3-EL and E, E/A, e, e/a (P<0.05); and positive correlation between P5-EL and e, e/a (P<0.05). In DCM group, EL was positively correlated with E, E/A, e, e/a at the P1、P3(P<0.05). P2-EL was positively correlated with E、E/A、e、e/a、E/e,and negatively correlated with e/a(P<0.05).Conclusions: The changes of heart struture and function in patients with DCM induced the abnormal vorticity and increased the EL in most phases. VFM technology could visually detect and quantify blood flow changes and EL characteristics of DCM subjects in the left ventricular cavity and measure vortex circulation, EL. The present study provides reference values for quantitative evaluation on blood flow changes of left ventricular in DCM patients. The parameters of EL could sensibly reflect changes in left ventricular hemodynamics. The EL value mighted to be a new indicator of assessment of the ventricular diastolic dysfunction.