Xue-cun Liang

New two-dimensional global longitudinal strain and strain rate imaging for assessment of systemic right ventricular function

Objectives: To determine the usefulness of new two-dimensional strain indices, based on speckle tracking imaging, for assessment of systemic right ventricular (RV) function after an atrial switch operation for transposition of the great arteries. Design: Cross-sectional study. Setting: Tertiary paediatric cardiac centre. Methods: 26 patients, mean (SD) age 21.0 (3.6) years at 19.9 (3.2) years after an atrial switch operation, and 27 age-matched controls were studied. Two-dimensional imaging at the four-chamber view was obtained with tracing of the entire RV endocardial border. The RV global longitudinal strain (GLS) and GLS rate were derived using automated software (EchoPAC, GE Medical) and correlated with tissue Doppler-derived RV isovolumic acceleration (IVA), and, in the patient cohort, with cardiac magnetic resonance-derived RV ejection fraction. Results: Intra- and interobserver variability for measurement of GLS, as determined from the mean (SD) of differences in two consecutive results from 20 studies, were 0.06 (1.39)% and 0.24 (1.77)%, respectively. Compared with controls, patients had lower RV GLS (17.1 (1.9)% vs 26.3 (2.9)%, p<0.001), a reduced GLS rate (0.78 (0.11)/s vs 1.33 (0.23)/s, p<0.001), lower RV IVA (1.10 (0.36) m/s2 vs 1.56 (0.53) m/s2, p<0.001) and increased RV myocardial performance index (0.52 (0.09) vs 0.38 (0.09), p<0.001). Both RV GLS and GLS rate correlated positively with RV IVA (r = 0.43, p = 0.001 and r = 0.46, p<0.001, respectively), and negatively with RV myocardial performance index (r = −0.65, p<0.001 and r = −0.57, p<0.001, respectively). In patients, the GLS rate correlated positively with RV ejection fraction (r = 0.62, p = 0.001). Conclusions: Two-dimensional RV GLS and GLS rate are new, potentially useful indices for assessment of systemic RV function.

Impact of Right Ventricular Dilation on Left Ventricular Myocardial Deformation in Patients After Surgical Repair of Tetralogy of Fallot

Left ventricular (LV) dysfunction is 1 of the major determinants of late adverse clinical outcomes in patients after surgical repair of tetralogy of Fallot (TOF). The aim of this study was to test the hypothesis that LV myocardial deformation is impaired in patients after TOF repair and related to right ventricular (RV) dilation and exercise capacity. Longitudinal, radial, and circumferential LV myocardial deformation was determined using speckle-tracking echocardiography in 23 postoperative patients with TOF and compared to that of 23 age-matched controls. Relations between LV strain and strain rate (SR) and RV volumes and exercise parameters were determined in patients. Compared to controls, patients had reduced global LV longitudinal, radial, and circumferential strain (all p values <0.05). Patients with significantly increased RV end-systolic volume (>2 SDs higher than normal; n = 17) had reduced global LV circumferential strain (p = 0.048) and SR (p = 0.038), but similar longitudinal and radial speckle-tracking echocardiographic parameters, compared to those without (n = 6). RV end-systolic volume was correlated inversely with global LV circumferential strain and SR (r = -0.58, p = 0.004, and r = -0.58, p = 0.005, respectively), while RV end-diastolic volume was correlated only with global LV circumferential strain (r = -0.43, p = 0.047). In patients, the LV ejection fraction was correlated with global LV circumferential strain (r = 0.54, p = 0.01) and SR (r = 0.66, p = 0.001) but not with longitudinal or radial speckle-tracking echocardiographic parameters. Using multivariate analysis, global LV circumferential SR (beta = 0.66, p = 0.001) and male gender (beta = 0.46, p = 0.012) were identified as independent predictors of peak oxygen consumption. In conclusion, the negative impact of RV dilation on LV function relates to its influence on LV circumferential strain and SR in patients after TOF repair.

Impact of Right Ventricular Volume Overload on Three-Dimensional Global Left Ventricular Mechanical Dyssynchrony After Surgical Repair of Tetralogy of Fallot

This study aimed to test the hypothesis that right ventricular (RV) volume overload may result in left ventricular (LV) systolic dysfunction through induction of LV systolic dyssynchrony after tetralogy of Fallot (TOF) repair. Sixty patients with TOF repair were studied at 14.3 +/- 7.2 years after TOF repair. Real-time 3-dimensional echocardiographic data sets were acquired for measurement of LV and RV volumes and derivation of ejection fractions and pulmonary regurgitant volume. The LV systolic dyssynchrony index (SDI) was derived from the dispersion of time to minimum regional volume using a 16-segment model. The results were compared with those of 29 healthy controls. LV SDI was significantly higher in patients than controls (7.4% +/- 2.0% vs 3.0% +/- 0.9%, p <0.001). The prevalence of LV mechanical dyssynchrony (SDI >4.7%) in patients was 93% (95% confidence interval 87% to 100%). The time to minimum regional volume was significantly longer in all of the 6 basal segments and the midposterior segment (all p <0.05) in patients than controls. Multivariate analysis identified RV end-diastolic volume (beta = 0.58, p <0.001), LV ejection fraction (beta = -0.38, p <0.001), and LV end-diastolic volume (beta = 0.26, p = 0.002) as significant correlates of LV SDI. In conclusion, in patients after TOF repair, RV volume overload has a negative effect on LV systolic function through induction of global LV mechanical dyssynchrony.

Inflammatory gene polymorphisms and susceptibility to kawasaki disease and its arterial sequelae.

OBJECTIVE. We tested the hypothesis that single-nucleotide polymorphisms of inflammatory genes C-reactive protein (CRP) and tumor necrosis factor α (TNF-α) may exert influence on susceptibility to Kawasaki disease and its arterial sequelae. METHODS. We analyzed the CRP +1444 C→T and TNF-α −308 G→A polymorphisms in 167 patients aged 8.9 ± 4.1 years with a history of Kawasaki disease (73 with and 94 without coronary aneurysms) and 124 healthy control subjects. For patients with Kawasaki disease, we further determined whether these single-nucleotide polymorphisms were associated with coronary aneurysms, carotid arterial stiffening, and intima-media thickness. RESULTS. Genotypic and allelic frequencies of CRP +1444 for T carrier and TNF-α −308 for A carrier were significantly higher in patients than in control subjects. The genotypic and allelic distributions did not differ between patients with and those without coronary aneurysms; however, patients with CRP +1444 CT/TT genotype compared with those with a CC genotype and patients with TNF-α −308 GA/AA genotype compared with those with a GG genotype had significantly greater carotid arterial stiffness and intima-media thickness. Carriers of both CRP +1444 T allele and TNF-α −308 A allele had the highest susceptibility to Kawasaki disease and a significant trend of increased arterial stiffness and intima-media thickness compared with those who carried either 1 or none of the rare alleles. Multiple linear regression analysis identified CRP +1444 allele carrier as a significant determinant of both carotid stiffness and carotid intima-media thickness and TNF-α −308 A allele carrier as a determinant of only intima-media thickness. CONCLUSIONS. Our findings suggest that CRP +1444 C→T and TNF-α −308 G→A polymorphisms are associated with predisposition to Kawasaki disease and, in patients with Kawasaki disease, increased carotid arterial stiffness and intima-media thickness in the long-term.

Restrictive Right Ventricular Physiology and Right Ventricular Fibrosis as Assessed by Cardiac Magnetic Resonance and Exercise Capacity After Biventricular Repair of Pulmonary Atresia and Intact Ventricular Septum

The hypertrophic myocardium, myocardial fiber disarray, and endocardial fibroelastosis in pulmonary atresia and intact ventricular septum (PAIVS) may provide anatomic substrates for restrictive filling of the right ventricle.

Myocardial Deformation in Patients with Beta-Thalassemia Major: A Speckle Tracking Echocardiographic Study

Background: Increasing data suggest that parameters of myocardial deformation are strong indices of ventricular systolic and diastolic function. We sought to determine myocardial deformation of the left ventricle and assess relationship of deformation rates with myocardial iron load in patients with beta‐thalassemia major. Methods: The left ventricular longitudinal, circumferential, and radial myocardial deformation was determined using speckle tracking echocardiography in 42 thalassemia patients aged 24.4 ± 6.4 years. The results were compared with those of 38 age‐matched controls. The rates of longitudinal and circumferential deformation were correlated with cardiac T2* magnetic resonance findings. Results: Compared with controls, patients had significantly greater global systolic radial strain (P = 0.001), but similar global systolic longitudinal (P = 0.12) and circumferential strain (P = 0.84). On the other hand, patients had significantly lower longitudinal systolic strain rate (SR) (P = 0.019), longitudinal early diastolic SR (P = 0.036), and circumferential early diastolic SR (P = 0.04) than controls. The cardiac T2* findings correlated positively with longitudinal (r = 0.44, P = 0.004) and circumferential early diastolic SR (r = 0.37, P = 0.019), but not with the respective systolic SRs and left ventricular ejection fraction (all P > 0.05). Patients with iron overload (T2*< 20 msec), compared to those without, had significantly lower longitudinal (1.45 ± 0.33/sec vs. 1.76 ± 0.27/sec, P = 0.002) and circumferential (1.01 ± 0.31/sec vs. 1.22 ± 0.31/sec, P = 0.03) early diastolic SR. Conclusions: Patients with beta‐thalassemia major have reduced longitudinal systolic SR, longitudinal early diastolic SR, and circumferential early diastolic SR. The rates of diastolic deformation in the longitudinal and circumferential dimensions are inversely related to myocardial iron overload. (Echocardiography 2010;27:253‐259)

Diastolic ventricular interaction in patients after atrial switch for transposition of the great arteries: A speckle tracking echocardiographic study

BACKGROUND We tested the hypothesis that diastolic ventricular interaction occurs after atrial switch operation for transposition of the great arteries (TGA) and that subpulmonary LV diastolic function is influenced by septal geometry. METHODS Twenty-nine patients (male 19) after atrial switch operation for TGA aged 20.8 ± 4.1 years and 27 healthy controls were studied. Two-dimensional longitudinal systolic strain, systolic (SRs), early diastolic (SRe), and late diastolic (SRa) strain rates of both ventricles were determined using speckle tracking echocardiography. Early diastolic trans-atrioventricular velocity (E) and myocardial early diastolic myocardial velocity (e) at the ventricular free wall-annular junction were measured. Geometry of the morphologic left ventricle was quantified by the diastolic eccentricity index (EI). RESULTS In both systemic and subpulmonary ventricles, SRe and SRa were significantly lower and trans-atrioventricular E/e ratios higher in patients than controls (all p<0.001). In patients, RV SRe correlated with left ventricular (LV) SRe (r=0.49, p=0.008), and RV SRa correlated with LV SRa (r=0.46, p=0.01). Significant leftward shifting of the septum in patients was reflected by the greater LV EI (p<0.001). In patients, LV EI correlated with age- and sex-adjusted z score of LV end-diastolic volume. As a group, LV EI correlated negatively with LV SRe (r=-0.62, p<0.001) and LV SRa (r=-0.51, p<0.001), and positively with mitral E/e ratio (r=0.33, p=0.02). CONCLUSIONS Systemic RV diastolic dysfunction occurs after atrial switch operation and correlates with subpulmonary LV diastolic dysfunction. The observed diastolic ventricular interaction may potentially be mediated through alteration of septal geometry.