Left Ventricular Twisting And Untwisting Assessed By Speckle Tracking Imaging

Background and purposes:More recently,the speckle tracking imaging (STI) has presented us the possibility of noninvasive measurement of left ventricular strain,velocity and displacement in an objective manner,with validation against sonomicrometry and cardiac MRI.However,there are limited data on the clinical application of twisting and untwisting for the assessment of LV function in patients with acute myocardial infarction and in hypertensive patients with left ventricular hypertrophy(LVH).The study included three parts.In the first part,we thought to investigate the effect of aging on LV twisting and untwisting. In the second part,STI was used to examine whether (LVH) adversely affects LV twisting and untwisting.Lastly,We investigated whether LV twisting and untwisting would be changed in anterior wall acute myocardial infarction (AMI) as a result of reduced apical rotation, and to demonstrate the relation of global LVcontraction with LV twisting and un-twisting in patients with anterior wall MI.PartⅠ:Age-related changes in left ventricular twisting and untwisting assessed by speckle tracking imagingMethods Ninety four healthy subjects were divided into four groups by age,a younger group (19-45years old),a middle age group (46-64 years old) an elder group (65-79years old) and very old group(≥80 years old).Basal and apical LV short-axis images were acquired in all people. Peak twist (Ptw),twist at aortic valve closure (AVCtw),twist at mitral valve opening(MVOtw),untwisting rate (UntwR),peak twist velocity (PTV),time to peak twist velocity (TPTV),time to peak untwisting velocity (TPUV) were separately measured.Results With aging, Ptw,AVCtw,MVOtw and PUV increased significantly(P<0.05) and UntwR decreased significantly (P<0.05).Whereas no difference in TPUV,PTV and TPTV were noted among the 4 groups(P>0.05).Conclusions The age-related changes of LVtw and untwisting could be evaluated by STI,and LV diastolic function could be affected by age.Part II:Left Ventricular Twisting and Untwisting in Patients with Hypertension and Left Ventricular Hypertrophy Using Speckle Tracking ImagingMethods Basal and apical LV short-axis images were acquired in 50 hyper-tensive patients and 29 normal people.Using two-dimensional strain software,a time-domain speckle tracking was performed,and the mean value of LV rotation was obtained at each plane.Ptw,AVCtw,MVOtw,UntwR,PTV,TPTV,PUV,TPUV were separately measured.Results Compared with normal group,Ptw,AVCtw and MVOtw were significantly higher in hypertensive patients with LVH (P＜0.05). Compared with normals and mild LVH group,the UntwR during isovolumic relaxation period in patients with moderate-severe LVH reduced significantly (P<0.01).③Although PTV,PUV and TPTV were not different among three groups, TPUV was delayed significantly in moderate-severe LVH group (P<0.05). Conclusion STI is a novel tool which could quantified the changes of LV function caused by deformation of LV in hypertensive patients with LVHPart III The Assessment of Left Ventricular Twisting and Untwisting in Anterior Wall Acute Myocardial Infarction Using Speckle Tracking ImagingMethods Basal and apical LV short-axis images were acquired in 38 patients with anterior wall myocardial infarction and 20 healthy subjects.Patients were divided into two groups according to global LV systolic function [normal LV ejection fraction(LVEF) group (LVEF≥45%) and abnormal LVEF group (LVEF <45%)].The value of LV rotation at basal and apical levels of each plane were obtained and recorded.Ptw,AVCtw,MVOtw,UntwR,PTV,TPTV,PUV,TPUV were separately measured.Results Apical rotation was significantly reduced in abnormal EF group when compared with normal EF group and healthy group (P<0.01),Whereas no different changes at basal levels were noted among the three groups(P>0.05).Although PTV,PUV and TPTV were not different among the three groups,UntwR were significantly reduced in abnormal EF group(P<0.01) mainly because of reduced apical rotation,andPtw,AVCtw,MVOtw were also significantly depressed(P<0.05, respectively).Significant correlation was noted between untwisting rate and EF (r=0.63,P<0.001) and LV end systolic volume (r=0.52,P<0.001).Conclusions Left ventricular twisting and untwisting can be measured by STI.Systolic twisting and diastolic untwisting rate were decreased in accordance with LV systolic dysfunction in anterior wall MI.These results suggest the significant impact of LV systolic function on LV twisting and untwisting in patients with anterior wall MI.