Evaluation Of Left Ventricular Twist In Patients With Dilated Cardiomyopathy By Two-dimensional Speckle Tracking And Tissue Doppler Imaging

The alignment modality of cardiac muscle fibers and motion shape are paid close attention to in the study of cardiac mechanics. Left ventricular (LV) torsional deformation, a wringing motion as the apex rotates with respect to the base about the LV long axis, is thought to play an important role in cardiac contraction and relaxation.Patients with dilated cardiomyopathy (DCM) are often died of fatal heart failure. The exact cause of disease of DCM is still unclear. Generally believed that the virus infection is an important cause of DCM with the exception of idiopathic cause and familial inheritance. The coup injury resulted in by virus or Myocarditis caused by humoral or cell immune response can induce DCM. In addition, the perinatal period, alcoholism, antineoplastic agents, metabolic disorders and other factors can also cause this kind of disease. Study of recent years has confirmed that the pathogenesis of DCM has relation with autoimmune responses. The main performance of ventricular remodeling of DCM is ventricular spherical expansion. Myocardial cells inspected under microscope are degeneration, atrophy and fibrosis, but some cardiac myocyte is hypertrophy. Process of DCM is often diffuse distribution, but the main affection is damage of left ventricular. Ventricular mural thrombus is frequent. The process of DCM is slow and conceal. The cardiac function in patients with DCM aggravates progressively while heart failure. The early diagnosis and early treatment on DCM has become a international hot spot of research. To assess the value of left ventricular twist (LVtw) in Patients with Dilated Cardiomyopathy (DCM) by Echo Techniques, so that an effective tool can be provided to serve clinical early diagnosis and treatment of DCM.The study was divided into two parts as follows:part 1. The Assessment of Left Ventricular Twist in Patients with Dilated Cardiomyopathy Using Two-dimensional Speckle Tracking ImagingThe study subjects were divided into two groups: Basal and Apical LV short-axis images were acquired in 33 Patients with dilated cardiomyopathy and in 30 healthy volunteers. Using commercially available 2-dimensional strain software, time domain Speckle tracking was performed, and regional LV rotation were obtained in each plane. LV twist was calculated as apical LV rotation relative to the base.Results:①As seen from the apex, LV performs a wringing motion with a clockwise rotation at the base and counterclockwise rotation at the apex.②LV Peak twist (Ptw) was significantly reduced in DCM (﹝6.56±2.19﹞vs﹝14.44±1.55﹞, P < 0.05) because of reduced apical rotation and basal rotation.③There was significantly correlation between LV Ptw and global LV systolic function (r = 0.762,P = 0.00). Part 2. The Assessment of Left Ventricular Twist in Patients with Dilated Cardiomyopathy Using Quantitative Tissue Velocity ImagingBasal and Apical LV short-axis images were acquired in 30 Patients with dilated cardiomyopathy (DCM) and in 32 healthy volunteers. Using commercially available Q-Analysis software, regional LV velocity imaging and displacement profiles were obtained in each plane. LV Systolic Lateral-septal maximum displacement diference (SDl-s) was defined as LV Lateral wall velocity relative to the septum. LV Twist Motility Index (TMI) was defined as apical LV SDl-s relative to the base in systolic phase. Using commercially available 2-dimensional strain software, time domain Speckle tracking was performed, and regional LV rotation were obtained in each plane. LV twist (LVtw) was defined as apical LV rotation relative to the base.Results:①As seen from the apex, the normal LV performs a wringing motion with a clockwise rotation at the base and counterclockwise rotation at the apex.②LV Torsional Motility Index (TMI) was significantly reduced in patients with DCM (﹝12.33±3.29﹞vs﹝8.43±2.27﹞, P < 0.05) compared with healthy volunteers because of reduced apical Dl-s and basal Dl-s.③LV Peak twist (Ptw) was significantly reduced in DCM because of reduced apical rotation and basal rotation.④These results suggest the significant impact of LV TMI on global LV systolic function (r = 0.517, P < 0.01).⑤There was significant correlation between TMI and Ptw (r = 0.488, P < 0.01). Conclusions: Under the conditions of the present experiment, we concluded as follows:①LV twist (LV tw) was significantly reduced in DCM.②Two-dimensional ultrasound speckle-tracking imaging (STI) can evaluate LV twist. This novel method may promote noninvasive serial evaluations of the LV torsional behavior in clinical settings and provide unique and valuable information to patients with heart disease.③High frame-rate QTVI technique appears a promising quantitative tool to accurately provide the phase motility information. QTVI technique would be more robust in evaluation the left ventricular twist in clinical use.