Evaluation of left ventricular function in patients with dilated cardiomyopathy using vector flow mapping / 中华超声影像学杂志

ABSTRACT

Objective To observe the blood flow changes of left ventricular cavity and quantify the energy loss (EL) and circulation of left ventricular during systole and diastole in patients with dilated cardiomyopathy(DCM) via vector flow mapping(VFM).Methods Thirty-six healthy volunteers and 32DCM patients were enrolled.According to the severity of mitral regurgitation(MR),DCM patients were divided into two groups.The quantitative parameters,including average energy loss(EL-base,EL mid,EL-apex) and circulation (vortex quantity,vortex area,circulation) were measured in the different periods of VFM imaging mode in apical four-chamber view,apical three-chamber view and apical two-chamber view respectively.The difference of parameters was evaluated between different groups during the different periods.The early transmitral valve blood flow velocity E,the late transmitral valve blood flow velocity A,the ratio of early transmitral valve blood flow velocity to the early diastolic mitral valve velocity E/e,the ratio of early transmitral valve blood flow velocity to the late transmitral valve blood flow velocity E/A and Tei index were derived via dual-Doppler imaging technology.Meanwhile,the correlation between VFM parameters with E,A,E/A,E/e or Tei index was also analyzed.Results ①The level of EL were decreased significantly among EL-mid and EL-apex during early diastole,EL-mid during mid-systole,EL-mid and EL-apex during late-systole (P ＜0.05),when compared with the control group.The vortex quantity,vortex area and circulation during early diastole and the vortex area and circulation during atrial contraction period were significantly different between two groups (all P ＜ 0.05).As for mid-diastole,only vortex area showed significant difference (P ＜0).01).(②) When compared with different grades of MR in DCM patients,the level of all segments EL during diastole and EL-base during systole increased with severity of MR(P ＜0.05).The circulation during diastole also increased with the severity of MR(P ＜0.05).③The vortex area and circulation had positive correlation with E/e during diastole in all subjects(all P ＜0.05).The vortex area during atrial contraction period and early diastole had positive correlation with E/A and Tei index in all subjects(r =0.630,0.345,0.468,0.316,0.663,0.264,respectively,allP ＜0.01).EL-mid during late-systole were negatively correlated with LV end diastolic volume,end systolic volume,but positively correlated with ejection fraction in all subjects(r =0.335,-0.312,0.340,respectively,all P ＜0.05).While,there was positive correlation between E/A with the basal segment of mid-diastole(r =0.376,P ＜0.01).Conclusions The visualization of hydromechanics inside the heart of DCM patients could be directly accomplished by VFM,which can provide a new method for diagnosis and evaluation of DCM.