ABSTRACT
Objective To evaluate left ventricular (LV) remodeling and function after acute myocardial infarction (MI) in rats using speckle tracking imaging (STI). Methods The left anterior descending coronary was ligated to induce MI in twenty normal rats. One day after creation of MI, fifty survivals based on the diagnostic criteria of MI were divided into 4 groups as follows:pre-infarction, 1 day,4weeks,and 8 weeks after MI. Echocardiography was performed to evaluate the changes of left ventricularfunction in rats. M-mode and two-dimensional cross-sectional echocardiography data were acquired at the papillary muscle level and digitally stored for further analysis. Circumferential strain rate(SRcir) and radial strain rate(SRrad) indexes were measured by STI software for each animal. Results One day after MI,indexes of SRcir and SRrad in anterior and lateral segments were significantly decreased (P ＜0.01, for both). Four weeks after MI,compared with baseline,SRrad and SRcir were decreased in all segments ( P ＜0.01). Eight weeks after MI, however, SRrad and SRcir showed no significant difference compared with 4weeks group. Conclusions STI can correctly identify LV dysfunction in rats and can be used for serial assessment of cardiac remodeling in rats models.
ABSTRACT
Objective To evaluate the therapeutic effects of rAAV2-SERCA2a gene targeted to myocardium by the ultrasound mediated microbubbles in rats with myocardial infarction(MI) using speckle tracking echocardiography (STE). Methods Thirty-five male SD rats were divided into Sham group, MI group and gene therapy group. rAAV2-SERCA2a was attached to the surface of SonoVue, sulphur hexafluoride-filled microbubbles. Therapy group animals were infused with those mixed fluids through tail vein. The other two groups were infused with SonoVue microbubbles. These bubbles were infused with simultaneous echocardiography. Four weeks after ultrasound microbubbles destructed,Circumferential strain rate(SRcir), radial strain rate(SRrad) and left ventricular torsion (LVtor) of regional myocardium were measured in short-axis view using speckle tracking imaging software for each animal. Results Compared with the M1 group,there were significant increase in SRcir-S,SRcir-E, SRrad-S,SRrad-E and LVtor in rats of gene therapy group( P ＜0. 01 ). There was no significant difference between gene therapy group and sham group. Conclusions rAAV2-SERCA2a gene targeted to myocardium by the ultrasound mediated microbubbles could enhance cardiac function of rats with MI.
ABSTRACT
Objective To evaluate the relationship among segmental dyssynchrony indexes, reginal ejection frction(EF) and global EF of left ventricle(LV) in the patients with dilated cardiomyopathy. Methods Standard deviation(SD) and maximal difference (Dif) in the time to minimal systolic volume in user-selected LV segments (Tmsv SeI-SD, Tmsv SeI-DIF) of LV global EF (LV-EF), reginal ejection fraction (REF) were acquired by real-time three-dimensional echocardiography in 27 controls and 24 DCM dyssynehrony patients. Data were grouped separately for 3 levels of the basal, mid and apical segments. Results The values of Tmsv SeI-SD and Tmsv SeI-DIF were linearly negatively correlated with REF in mid segment of DCM (r =-0.6921,-0.6384, P<0.01). It existed exclusive linear regression between Tmsv Sel-SD,Tmsv SeI-DIF and LV-EF only in mid segment's dyssynchrony indexes among three segments(β= -0.7836, -0.7801, P<0.01). Each REF in three segments was linear regression relationship with LV-EF(β= 0.2234,0.7506,0.1880, P <0.05) especially in mid segment. Conclusions The Tmsv SeI-SD, Tmsv SeI-DIF and REF of mid segment are important factors to influence left ventricular function in the patients with dilated cardiomyopathy.