Zhi-An Li

Assessment of Cardiac Twist in Dilated Cardiomyopathy Using Velocity Vector Imaging

Objectives: Velocity vector imaging (VVI) is a novel echocardiography technique to assess myocardial motion in two dimensions. In this study, we used VVI to assess left ventricular twist (LVtwist) in dilated cardiomyopathy (DCM) patients. Methods: Twenty DCM patients and 31 normal subjects were evaluated. Echocardiographic images of the long and short axis were processed by VVI software to measure peak rotation angle (ProtA), peak rotation rate (ProtR) in systole. In addition, peak untwisting velocity (Pun‐twV) and untwisting rate (unTwR) were measured in diastole. LVtwist was defined as the net difference between the apical and basal angle of rotation, left ventricular torsion (LVtor) was calculated as LVtwist divided by left ventricular diastolic longitudinal length. Results: The pattern of LVtwist was normal (apex counterclockwise, base clockwise) in 16 DCM patients but abnormal in four. LVtwist and LVtor were significantly decreased (P < 0.01) in DCM compared with normals. In addition, ProtA, ProtR, Pun‐twV, and unTwR were all decreased at the basal and apical levels in DCM compared with normals (P < 0.01). There was a significant correlation between ejection fraction and LVtwist in the DCM patients (r = 0.489, P < 0.05). Conclusions: Cardiac twist is impaired in DCM and this impairment is linked to global dysfunction. VVI is a new noninvasive technology that can be used to assess cardiac twist. (ECHOCARDIOGRAPHY 2010;27:400‐405)

New pulmonary vein Doppler echocardiographic index predicts significant interatrial shunting in secundum atrial septal defect

BACKGROUNDnThe relation between pulmonary venous flow (PVF) pattern and degree of left-to-right interatrial shunting (IAS) in patients with secundum atrial septal defect (ASD) is unknown.nnnMETHODSnFifty consecutive ASD patients (14 males, 36 ± 17 years) received transthoracic echocardiography (TTE) before and 1 day after transcatheter closure and their results were compared to 40 controls. The ratio of pulmonary-to-systemic flows (Qp/Qs) was assessed by TTE and invasive oximetry.nnnRESULTSnPre-closure PV systolic (PVs), diastolic (PVd) velocities and velocity-time integral (PV-VTI) increased, time from onset of ECG Q-wave to the peak PV diastolic wave (Q-PVd) shortened and atrial reversal (PVar) velocity significantly decreased as compared to normals. These findings normalized after closure. Patients with large IAS (defined as invasive Qp/Qs ≥ 2) had higher PVs, PVd and PV-VTI, shorter Q-PVd but lower PVar (all p<0.01) than those with small IAS. Invasive Qp/Qs ratios correlated with PVs, PVd, PV-VTI, Q-PVd and TTE-derived Qp/Qs ratios, ASD sizes and RV end-diastolic dimensions (all p<0.05). PV-VTI (β=0.49) and ASD size (β=0.48) remained independent predictors of large IAS after multivariate analysis. The corresponding sensitivity, specificity and AUC were 89%, 82% and 0.90 respectively for a PV-VTI of 30 cm (p<0.001).nnnCONCLUSIONnASD patients with significant IAS have distinguishable PVF features. Doppler evaluation of PV-VTI is a novel additional tool for assessing the magnitude of shunting in these patients non-invasively.

Early Detection of Regional and Global Left Ventricular Myocardial Function Using Strain and Strain-rate Imaging in Patients with Metabolic Syndrome

Background: Strain and strain-rate imaging (SRI) have been found clinically useful in the assessment of cardiac systolic and diastolic function as well as providing new insights in deciphering cardiac physiology and mechanics in cardiomyopathies, and identifying early subclinical changes in various pathologies. The aim of this study was to evaluate the regional and global left ventricular (LV) myocardial function in metabolic syndrome (MS) with SRI so that we can provide more myocardial small lesions in patients with MS, which is robust and reliable basis for early detection of LV function. Methods: Thirty-nine adults with MS were enrolled in the study. There was a control group of 39 healthy adults. In addition to classic echocardiographic assessment of LV global functional changes, SRI was used to evaluate regional and global LV function. Including: Peak systolic strain (S), peak systolic strain-rate (SR-s), peak diastolic strain-rate (SR-e). Results: There were no statistically significant differences between MS and controls in all traditional parameters of LV systolic function. On the other hand, significant differences were observed between MS and the control group in most of the parameters of S, SR-s, SR-e in regional LV function. Multiple stepwise regression analyses revealed that S and SR significantly were negatively correlated with blood pressure, waist circumference, fasting plasma glucose, uric acid, suggesting that risk factories were relevant to regional systolic dysfunction. Conclusion: In MS with normal LV ejection fraction, there was regional myocardial dysfunction, risk factors contributed to the impairment of systolic and diastolic function of the regional myocardium. Assessment of myocardial function using SRI could be more accurate in MS patient evaluation than conventional echocardiography alone.

Effect of Smoking on Common Carotid Artery Wall Elasticity Evaluated by Echo Tracking Technique

The aim of this study was to examine the applicability of echo tracking to evaluation of common carotid artery wall elasticity in smokers and the effects of hypertension, hyperlipidemia and hyperglycemia on common carotid artery wall elasticity in smokers. Subjects were divided into three groups based on smoking status and presence of complications: group A (healthy control group), group B1 (simple smoking group) and group B2 (smoking with complications group). Complications included one or several symptoms of hypertension, hyperlipidemia and hyperglycemia. Intima-media thickness (IMT) of the common carotid artery was measured with ultrasound, and wall stiffness index(β), pressure-strain elasticity modulus (Ep), arterial compliance, augmentation index and local pulse wave velocity (PWVβ) were measured with echo tracking. We also determined the systolic (Ds) and diastolic (Dd) lumen diameters of the common carotid artery and systolic (Ps) and diastolic (Pd) pressures. The differences in β, Ep and PWVβ among the three groups in this study were statistically significant (pxa0<xa00.05). Augmentation index was increased in group B2 compared with groups B1 and A, with the differences being statistically significant (pxa0<xa00.05). Differences in augmentation index between groups B1 and A, differences in arterial compliance among the three groups and differences in intima-media thickness among the three groups were not statistically significant (pxa0>xa00.05), but differences in Ds and Dd among the three groups were statistically significant (pxa0<xa00.05). Differences in Ps and Pd between groups A and B1 were not statistically significant (pxa0>xa00.05), whereas those between groups B1 and B2 were statistically significant (pxa0<xa00.05). Echo tracking can be used to quantitatively evaluate the effect of smoking on common carotid artery wall elasticity and the effects of hypertension, hyperlipidemia and hyperglycemia on common carotid artery wall elasticity in smokers.

Left anterior descending coronary artery flow impaired by right ventricular apical pacing: The role of systolic dyssynchrony

INTRODUCTIONnRight ventricular (RV) pacing may affect myocardial perfusion and coronary blood flow; however, it remains unknown whether this is related to systolic dyssynchrony induced by RV pacing. This prospective study was aimed to assess the relationship between dyssynchrony and the changes of coronary blood flow.nnnMETHODSnSeventy patients with sinus node dysfunction were prospectively enrolled. Coronary flow was evaluated by measuring diastolic velocity time integral (VTI) and duration at the distal-portion of left anterior descending coronary artery (LAD) with transthoracic echocardiography at baseline and follow-up. Systolic dyssynchrony was assessed with tissue Doppler imaging by time standard deviation to peak systolic velocity of 12 left ventricular segments (Ts-SD, cutoff value ≥ 33 ms).nnnRESULTSnAdequate data for analysis was available from 65 patients. At follow-up (mean follow up time: 127 ± 45 days), LAD velocity-time integral (LAD-VTI: 12.1 ± 4.2 vs. 10.7 ± 4.6 cm, p<0.001) was decreased and there was deterioration of left ventricular systolic function (left ventricular ejection fraction: 65 ± 7% vs. 62 ± 7%). However, these changes were only detected in those with RV pacing induced systolic dyssynchrony. Significant reduction of LAD-VTI (defined as ≥ 5%) occurred in 34 (52%) patients which was more prevalent in those with pacing-induced systolic dyssynchrony than those without (85.3% versus 16.1%, χ(2)=31.1, p<0.001). Though similar at baseline, LAD-VTI was significantly lower in the dyssynchrony group at follow up (p<0.001). Cox-regression analysis showed that pacing-inducing systolic dyssynchrony [hazard ratio (HR): 3.62, p=0.009] and higher accumulative pacing percentage (HR: 1.02, p=0.002) were independently associated with reduction of LAD-VTI. ROC curve demonstrated that accumulative pacing percentage ≥ 35% was 97% sensitive and 84% specific in revealing significant reduction (area under the curve: 0.961, p<0.001).nnnCONCLUSIONSnRV pacing induced dyssynchrony is associated with reduced coronary flow and this may account for, in part, the deleterious effect of RV pacing on ventricular function over time.

Deciphering the mysteries of crisscross heart by transthoracic echocardiography.

Background: Accurate diagnosis of crisscross heart and its associated anomalies is important but problematic for cardiologists. This study aimed at identifying unique transthoracic echocardiographic features and common associated lesions of this complex condition. Method: Clinical and echocardiographic features of 10 patients with crisscross anatomy were studied. Echocardiographic findings were verified by cardiac magnetic resonance imaging or surgical inspection. Results: Crisscross anatomy (10 patients, age at diagnosis ranged from 1 month to 25 years, five female) was identified in 0.076% of patients with congenital heart diseases from 1985 to 2006. All patients had cyanosis and 80% of them were underweight. Superior–inferior ventricles (SIV) and crossed ventricular inflow streams were seen in 90% and 100% of patients, respectively. All patients had abnormal ventriculo–arterial (VA) connections: five with transposition of great artery (L‐type: n = 2; D‐type: n = 3) and five with double outlet right ventricle. Commonly associated anomalies included ventricular septal defects (100%), right ventricular outflow tract obstruction (60%), atrioventricular valves straddling or overriding (50%), atrial septal defect (40%), and right ventricular hypoplasia (30%). Seven patients received cardiac surgery for the relief of cyanosis. Conclusions: SIV and crossed inflow streams are important diagnostic features for crisscross heart by transthoracic echocardiogram. The hemodynamic consequences of abnormal VA connections and associated defects impact surgical management. (Echocardiography 2011;28:104‐108)

Regional Atrial Myocardial Velocity in Normal Fetuses: Evaluation by Quantitative Tissue Velocity Imaging

Objectives: Quantitative tissue velocity imaging (QTVI) is a new noninvasive method that derives measurements of velocities directly from the myocardium. Data on atrial myocardial tissue velocities in normal fetuses have not been established. The objective of this study was to evaluate atrial myocardial velocity and the myocardial velocity gradient of normal fetuses by using QTVI. Methods: We measured motion velocities of the left and right atrial wall along the long axis in 50 normal fetuses aged 21–32 weeks gestation (mean, 25.3 ± 2.8 weeks). In all fetuses, peak myocardial velocity during early diastole (EW), atrial contraction (AW), and ventricular systole (SW) waves was recorded in the basal and mid‐atrial segments. Correlation analysis was conducted between segmental velocities of the left atrium (LA) and right atrium (RA) and gestational age. Results: The mean values for EW, AW, and SW of the long axis in the same right basal segment of the RA were greater than those of the LA (P < 0.01). There was a degressive gradient with velocity from the basal to superior in the atrial wall. There was a linear relationship with gestation for all basal myocardial velocities of the left and right atrial free wall (P < 0.05). However, the myocardial velocity variables of the midatrial wall showed no age‐dependence. Conclusion: We demonstrated that QTVI is reproducible and provides readily obtained parameters that provide unique data regarding segmental atrial myocardial velocity in normal fetuses. (Echocardiography 2012;29:182‐186)

Identification of Unusual Conditions after Atrial Septal Defect Repair by Systematic Transthoracic Echocardiographic Assessment

Background: There is a lack of echocardiographic studies to address the detection of atrial masses and abnormal venous connections in patients with secundum atrial septal defect (ASD) repair. This study sought to demonstrate that with proper technique, these unusual conditions could be diagnosed confidently by transthoracic echocardiography. Method: We performed a retrospective review of all repaired ASD patients of all ages with follow‐up echocardiography done at Beijing Anzhen Hospital from year 1999 to 2005. Clinical and echocardiographic features of patients with aforementioned conditions were evaluated. Results: Systematic echocardiographic protocol identified 11 patients with unusual conditions, in whom four patients had atrial masses (three atrial thrombi, one inflammatory pseudotumor) and seven patients had abnormal venous connections (two inadvertent diversion of inferior vena cava to left atrium, five previously unrecognized partial anomalous pulmonary venous connections). Conclusion: Atrial masses and abnormal venous connections could be diagnosed through a systematic echocardiographic approach in evaluating patients with ASD repair.

Assessment of Retrograde Coronary Venous Infusion of Mesenchymal Stem Cells Combined with Basic Fibroblast Growth Factor in Canine Myocardial Infarction Using Strain Values Derived from Speckle-Tracking Echocardiography.

Speckle-tracking echocardiography was used to assess retrograde coronary venous infusion of mesenchymal stem cells (MSCs) combined with basic fibroblast growth factor (bFGF) in a canine model of acute myocardial infarction (AMI). AMI was induced by ligation of the left anterior descending coronary artery. Coronary venous retroperfusion was performed at 1 wk after AMI. Twenty-eight animals were randomized into four groups: saline, bFGF+saline, saline+MSCs and bFGF+MSCs. Echocardiography was performed before AMI, at 7 d post-AMI and 40 d after retroperfusion. Apoptotic cardiomyocytes in the border zone of the ischemic region were evaluated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling. Vascular endothelial growth factor and factor VIII concentrations were measured by western blotting. The left ventricular end-systolic volume increased significantly, whereas the left ventricular ejection fraction and global and segmental strain values decreased significantly after AMI. After retroperfusion, the strain values of the infarct zone, but not conventional echocardiographic parameters, were significantly different between control and bFGF+MSC groups. Cardiomyocyte apoptosis decreased, whereas vascular endothelial growth factor and factor VIII concentrations were higher in the bFGF+MSC, bFGF and MSC groups. Cardiomyocyte apoptosis was well correlated with the strain values. Although retrograde coronary venous infusion of bFGF and MSCs promoted neo-vascularization of the infarcted myocardium and inhibited apoptosis, there was only a slight strain improvement without a substantial increase inxa0global cardiac functions.

Ultrasound Bio-microscopy for Measurement of Coronary Artery Flow and Estimation of Infarct Size in a Mouse Model of Acute Myocardial Infarction

Ultrasound bio-microscopy was used to measure hemodynamic changes in the left main coronary artery after myocardial infarction (MI), and its usefulness in estimating infarct size was evaluated. MI was induced by left anterior descending artery ligation. Diastolic peak velocity (Vd), mean flow velocity (Vmean) and the velocity-time integral (VTI) were measured 2 and 6xa0h after MI. Serum troponin I levels were assayed 2, 6 and 12xa0h after MI. At 2xa0h, Vmean and VTI significantly differed between mice that underwent low and high left anterior descending artery ligation; Vd, Vmean and VTI were correlated with infarct size (rxa0=xa0-0.557, -0.693 and -0.672, respectively; all pxa0<xa00.01). Infarct size was more strongly correlated with 2-h ultrasound bio-microscopy measurements than with 2-h serum troponin I level. Measurement of coronary artery blood flow by ultrasound bio-microscopy may be useful for early estimation of infarct size in mice.