ABSTRACT
Quantification of right ventricular(RV)volume and function remains a challenge because of RV complex geometry by conventional echocardiography.The purpose of this study was to assess RV global longitudinal function in patients with tetralogy of Fallot(TOF)by 2-dimensional ultrasound speckle tracking imaging(STI).Thirty-eight patients with TOF were enrolled in this study and divided into child group(n=25)and adult group(n=13)according to age.Thirty-eight age-and sex-matched normal subjects were selected as control groups including child control group(n=25)and adult control group(n=13).RV global longitudinal peak systolic strain(GLS),strain rate(GLSPs),early diastolic strain rate(GLSRe)and late diastolic strain rate(GLSRa)were measured in all subjects by STI from the apical 4-chamber view and compared between groups.Furthermore,the main factors affecting the RV global longitudinal functional parameters were assessed.Compared with those in controls,RV GLS,GLSRs and GLSPe were significantly reduced in patients with TOF(P<0.05 for all).RV GLSRs was significantly decreased in adult patients with TOF as compared with that in child patients(P<0.05).There was no significant difference in RV GLS,GLSRe and GLSRa between child and adult TOF groups(P>0.05).The diameter of right ventricle,main pulmonary artery and ventricular septum defect had correlations with RV GLSRs(r1=-0.490,r2=0.580,r3=-0.528,respectively,P<0.05 for all).Tricuspid annular plane peak systolic velocity(Sm)was the independent predictor of RV global strain and strain rate(β1=0.355,P1=0.031,β2=0.307,P2=0.021).RV global longitudinal function is decreased in patients with TOF,especially in adult patients.STI is a sensitive and accurate technique in RV global functional assessment.
ABSTRACT
This study evaluated the change in regional left ventricular myocardial function in rats following acute occlusion of the left anterior descending coronary artery (LAD) by using two-dimensional speckle tracking imaging (2D-STI). Sixty Wistar rats were randomly divided into two groups,a myocardial infarction (MI) group,in which 50 rats were subjected to LAD occlusion for 30-45 min,and a sham-operated (SHAM) group that contained 10 rats serving as control. Echocardiography was performed at baseline and 1,4 and 8 week(s) after the operation. High frequency two-dimensional images of left ventricular short axis at papillary muscle level were recorded. Peak systolic radial strain (PRS) and circumferential strain (PCS) were measured in the mid-ventricle in short-axis view by using EchoPAC workstation. Left ventrieular internal diameter at diastole (LVIDd)and systole (LVIDs),fractional shortening (FS),ejection fraction (EF) and left ventricular mass (LVM)were measured by anatomical M-model echocardiography. Infarct size was measured using triphenyl tetrazolium chloride (TTC) staining 1 week and 8 weeks after the operation. Fibrosis of left ventricular myocardium was displayed using Van Gieson staining 1 week after the infarction. In terms of the TTC staining results,the left ventricle fell into three categories:infarcted,peri-infarcted and remote myocardial regions. Compared with those at baseline and in the SHAM group,(1) PRS and PCS in the infarcted,peri-infarcted and remote myocardial regions were significantly decreased in the MI group within 1 week after the operation (P＜0.05) and the low levels lasted 8 weeks;(2) Compared with those at baseline,LVIDd,LVIDs,FS,EF and LVM in the MI group showed no significant difference 1 week after the operation (P＞0.05). However,LVIDd,LVIDs and LVM were increased significantly 4 and 8 weeks after the operation (P＜0.05),and FS and EF were decreased substantially (P＜0.05). Van Gieson staining showed that fibrosis developed in all the three myocardial regions to varying degrees. It is concluded that 2D-STI is non-invasive and can be used to assess regional function of myoeardium with different blood supply in rats following acute occlusion of the LAD,and can be used as a sensitive and reliable means to follow up the process of left ventricular remodeling.
ABSTRACT
To evaluate the feasibility of real-time myocardial contrast echocardiography (RTMCE) by quantitative analysis of myocardial perfusion in rabbits,transthoracic RTMCE was performed in 10 healthy rabbits by using continuous infusion of Sono Vue into the auricular vein. The short axis view at the papillary muscle level was obtained. The duration of the time that the contrast took to appear in right heart,left heart and myocardium was recorded. The regional myocardial signal intensity (SI) versus refilling time plots were fitted to an exponential function:y(t) =A(1-e-β(t-t0)) + C,where y is SI at any given time,A is the SI plateau that reflects myocardial blood volume,and β is the slope of the refilling curve that reflects myocardial microbubble velocity. The A,β and A×β values at different infusion rate of SonoVue were analyzed and the A,β and A×β values in each segment in the short axis view at the papillary muscle level were compared. All the animal experiments were successful and high-quality images were obtained. The best intravenous infusion rate for Sono Vue was 30 mL/h. The contrast appeared in fight heart,left heart and myocardium at 7.5±2.2 s,9.1±2.4 s and 12.2±1.6 s respectively. After 16.6±2.3s,myocardial opacification reached a steady state. The mean A,β and A×β value in the short axis view at the papillary muscle level were 9.8±3.0 dB,1.4±0.5 s 1 and 13.5±3.6 dB×s-1 respectively.A,β and A×β values showed no significant differences among 6 segments. It was suggested that RTMCE was feasible for quantitative analysis of myocardial perfusion in rabbits. It provides a non-invasive method to evaluate the myocardial perfusion in rabbit disease models.
ABSTRACT
To investigate the value of ultrasound speckle tracking imaging (STI) in the assessment of the short-axis and long-axis systolic function of the left ventricle (LV) in patients with type 2 diabetes mellitus (DM), 100 subjects with normal ejection fraction were studied, including 41 patients with DM only (DM group), 22 patients with both DM and left ventricular hypertrophy (DH group),and 37 healthy subjects (control group). Left ventricle systolic function in the long axis defined as longitudinal strain, and that in the short axis defined as radial strain, apical and basal LV rotations,and LV twist were assessed respectively. The results showed that average peak strain in the long axis at basal, middle and apical levels, and global peak strain were significantly decreased in the patient groups when compared with the control group (P<0.001 for each). The parameters in DH group were significantly lower than those in DM group (P<0.01 for each). There were no significant differences in average radial peak strain in the short axis at different levels, and global peak strain among the three groups (P>0.05). Apical and basal LV rotations, and LV twist were greater in the patient groups than in the control group (P<0.01 for each). Basal LV rotation and LV twist were greater in DH group than those in DM group (P<0.01). It was concluded that STI may be used to identify early abnormalities in patients with type 2 DM that have normal left ventricular systolic function.