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Objective To evaluate the left ventricular(LV) torsion and rotation in normal subjects using vector velocity imaging.Methods LV basal and apical short-axis images were captured in 10 healthy individuals to estimate LV torsion and rotation using routine 2-dimensional echocardiography and vector velocity imaging. Results As viewed from LV apex,the systolic basal rotation was clockwise (negative value),and apical rotation was counterclockwise (positive Value). The apical peak systolic rotational velocity was significantly higher than the basal [endo:(150±62)°/s vs (114±65)°/s;epi:(81±40)°/s vs (55±28)°s,respectively,P＜0.01]. The peak systolic endocardial rotational velocity and rotation was significantly higher than epicardial rotational velocity and rotation[basal:(-114±65)°/s vs (-55±28)°/s,(-12±6)°vs (-4±1)°;apical:(150±62)°s vs (81±40)°s,(10±4)°vs(6±2)°,respectivelv,P＜0.05]. There were no significant differences in the time to peak systolic rotational velocity/rotation between basal endocardium/epicardium and apical endocardium/epicardium. Conclusions Vector velocity imaging can assess LV torsion and rotation non-invasively,and normal LV has a kind of characteristic motion of torsion.
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Obiective To observe the value of speckle tracking imaging(STI)in assessing left atrial(LA) function in patients with chronic heart failure(CHF).Methods Twenty-two patients with CHF[LVEF(37.1± 10.5)%]and twenty normal controls[LVEF(61.94±10.68)%]were studied.CHF group was subdevided into patients with normal or abnormal LV filling pressure.Velocity vector imaging(Siemens Medical Solutions)was used to acquire 2-D images at parasternallong axis and apical 4-chamber views.The LA dimension and volume,LV volume and ejection fraction,ratio of mitral valve E wave and mitral annulus velocity e'E/e')were measured. LA tangential and radial velocity(Vt-As,Vr-As)and time to peak velocity(TVt-As,TVr-As)were analysed on Syngo Workplace offline.Results Vt-As and Vr-As of the CHF group were significantly smaller than those of the controls(P＜0.05),and Vr-As was even decreased in patient with elevated LV filling pressure(P＜0.05), however,TVt-AS and TVr-AS didn't show evident impairment in the CHF group(P＞0.05).Vt-As and Vr-AS were closely correlated with LVEF,EDV and ESV(P＜0.05).Vt-As was negtively correlated with LA volume (P＜0.05).Conclusions STI can quickly and accurately assess LA function,and help to recognize patients with elevated LV filling pressure,which is useful in the risk stratification,treatment evaluation and prognosis prediction of CHF patients.
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Objective To study the effect of myocardial infarction induced by distal left ascending artery occlusion on left ventrieular(LV) synchronism. Methods Routine echocardiography and vector velocity imaging were performed within 2 hours before and 7-14 days after myocardial infarction by occluding distal left ascending coronary arteries in experimental pigs. Routine eehocardiographie parameters of LV, including end diastolic and systolic diameters, volumes, and spherical indexes were measured or calculated. Six segmental peak systolic velocity, strain and strain rate were compared between pre- and post-myocardial infarction. Results After myocardial infarction, LV end diastolic, end systolic long diameter and end systolic volume increased with decreased ejection fraction. With the 6 segmental systolic velocity, strain and strain rate significantly reduced,the mean 6-segmental time to peak strain rate delayed significantly. Conclusions Abnormal synchronism after myocardial infarction may aggravate LV systolic dysfunction.
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Objective To determine the accuracy and usefulness of dobutamine stress echocardiography(DSE) in detecting restenosis after percutaneous coronary intervention (PCI). Methods DSE was conducted in 47 patients before coronary angiography, 6 months to 18 months after PCI. The standard protocol of DSE was 5,10,20,30 ?g?kg~(-1)?min~(-1) with subsequent incremental increases every 3 minutes to a maximum dose of 40 ?g?kg~(-1)?min~(-1). Consistency of the results was compared between DSE and coronary angiography.Results Compared with coronary angiographic results, DSE had a low sensitivity(64%) but high specificity(86%) for detection of restenosis after PCI. The total accuracy was 72%. Conclusions DSE can assess restenosis after PCI with lower cost and safety.
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Objective To evaluate the efficacy of a new micro-bubble contrast agent of C_3F_8 in the opacification of the left ventricle. Methods Seven pigs received a bolus injection of C_3F_8 (0.002) and (0.02) (ml/kg) intravenously. Left ventricular opacification grades and number of endocardial border delineation segments were observed and left ventricular ejection fraction(LVEF) were measured using modified Simpson method after each intravenous contrast injection. Heart rate and respiration rate were recorded before and after each injection. Results There was a significant improvement for every measurement of contrast enhancement in each intravenous injection. In addition, part of myocardial tissue could be enhanced after contrast injection. There was no difference in heart rate and respiration rate between pre- and post-injection. Conclusions This new contrast agent is safe and helpful in delineating endocardial border of the left ventricle.
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Objective To evaluate the role of transeso phageal echocardiography(TEE) before chemical or electric cardioversion for non-vulvular atrial fibrillation. Methods Forty-three patients, confirmed non-vulvular atrial fibrillation, undertook anticoagulation or anti-platelet therapy and transthoracic echocardiography and TEE less than 24-48 hours prior to cardioversion. Results Two thrombi in the left atrial appendage and three spontaneous echo contrasts in the left atrium were evidenced. After anticoagulation or anti-platelet therapy, 39 patients undertook cardioversion therapy. Among them,31 patients received drug cardioversion,success in 19,and failure in 12;8 patients received electric cardioversion,success in 6,and failure in 2. There were no thromboembolic events during the hospitalization. Conclusions TEE performed before cardioversion for atrial fibrillation is necessary to reduce the risks of thromboembolic events and to guide for anticoagulation therapy.