Evaluation Of The Left Ventricular Twist In Dilated Cardiomyopathy By Two-dimensional Ultrasound Speckle Tracking Imaging

Objective To assess the characters of left ventricular rotation (LVrot)and left ventricular twist (LVtw)in dilated cardiomyopathy (DCM)by two-dimensional ultrasound speckle-tracki- ng imaging (STI),to study the relationship between the twist and conventional echocardiogra- phic parameter of LV systolic function and to evaluate the LV synchrony and applying the Receiver Operating Characteristic (ROC) carves to evaluate its value in DCM .Methods 26 patients with dilated cardiomyopathy (14 men and 12 women,average age54.7±11.8 years) who were in the Affiliated Hospital of Ningxia Medical University between the November 2008 and the December 2009 and 26 age-matched healthy volunteers(18 men and 8 women,average age 52.3±9.4 years) were recruited. Echocardiography was performed in all cases and left ventricular ejective fraction(LVEF) was gotten. High frame rate two-dimensional images were recorded from the left ventricular short-axis views both of the basal and apical planes. Digital datas were stored in a hard disk for offline analysis using the EchoPAC software. Basal and apical peak value of left ventricular rotation (Prot), peak value of left ventricular twist (Ptw)and time to Prot and Ptw were calculated.The critical values of LV torsion were obtained by ROC curves.Result①Seen from the apex, LV performed a wringing motion with a counterclock- wise rotation at the apex and clockwise rotation at the base.The whole heart mainly performed a wringing motion with counterclockwise rotation within the cardiac cycle in all cases.②Compared with healthy volunteers ,peak apical rotation(PAR),peak basal rotation(P- BR) and peak twist (Ptw) were decreased significantly in DCM(P<0.001).③In DCM, PAR and Ptw were correlated with LVEF positively(r=0.640and0.617,P<0.05).④In DCM, there was significant difference in the time to Prot between the basal and apical level of the left ventricular(P<0.05).⑤The areas under the ROC curves of PAR and Ptw were 0.845 and 0.886,the cut-off values were 3.98°and 8.57°,the sensitivity were 88.5% and 88.5% and the specificity were 80.5% and 88.5%. The area under the ROC curves of PBR was 0.152 and there was no significant difference.Conclusion①From the left ventricular short-axis view, Lvrot and Lvtw are reduced significantly and the global LV is not synchrony in DCM,STI can evaluate the characters of left ventricular rotation (LVrot)and left ventricular twist (LVtw).②The decreased PAR and Ptw illustrate that LV systolic function is decreased, PAR and Ptw are correlated with LVEF which is a conventional echocardiographic parameter of LV systolic function.③The time to PAR and PBR provide a index for evaluating the LV synchrony.④To some extent,STI can be used to detect left ventricular torsional deformation of DCM.