Publications (85)369.09 Total impact
- [Show abstract] [Hide abstract] ABSTRACT: Background: This study tested the hypothesis that right atrial (RA) mechanics are altered in patients after repair of pulmonary atresia with intact ventricular septum (PAIVS) and pulmonary stenosis (PS) and to explore their relationships with right ventricular (RV) diastolic function and P-wave indices. Methods: Thirty-six adult patients, 16 with PAIVS and 20 with PS patients, and 20 age-matched healthy subjects were studied. Right atrial mechanics were assessed using speckle tracking echocardiography (STE) with quantification of positive, negative, and total strain, and strain rates at ventricular systole (aSRs ), early diastole (aSRed ), and atrial contraction (aSRac ). Right ventricular diastolic function was assessed by Doppler interrogation and STE. Maximum P-wave duration and P-wave dispersion were measured. Results: Compared with controls, PAIVS and PS patients had significantly lower RA positive and total strain, aSRs and aSRed (all P < 0.05). Parameters of RV diastolic function including transtricuspid early (E) and late (A) diastolic inflow velocities, E/A ratio, early diastolic tricuspid annular velocity (e), early to late diastolic annular velocity ratio, E/e ratio, and RV early diastolic strain rate were found to correlate significantly with RA positive and total strain and aSRed (all P < 0.05). Maximum P-wave duration and P-wave dispersion increased progressively across control, PS, and PAIVS groups (P for trend <0.001). Both P-wave indices correlated negatively with RA positive strain, total strain, and aSRed (all P < 0.05). Conclusion: Impairment of RA mechanics occurs in patients long term after repair of PAIVS and PS and is associated with RV diastolic dysfunction, longer P-wave duration, and greater P-wave dispersion.
- [Show abstract] [Hide abstract] ABSTRACT: Background: Disruption of pulmonary vasculogenesis occurs in bronchopulmonary dysplasia (BPD). Increased impedance to pulmonary flow secondary to abnormal vascular development may affect ventricular mechanics. Objectives: We aimed to test the hypothesis that cardiac mechanics are altered in prematurely born children with BPD. Methods: A cohort of 47 children was studied: 22 aged 48.9 ± 6.4 months born preterm with BPD (group I), 13 aged 46.3 ± 8.1 months born preterm without BPD (group II), and 12 healthy children aged 53.4 ± 12.2 months born at term (group III). Left (LV) and right ventricular (RV) strain and strain rate were assessed by speckle-tracking echocardiography. Results: The global RV systolic strain rate (p = 0.022) was significantly lower, while RV systolic strain (p = 0.05) and early diastolic strain rate (p = 0.05) and LV longitudinal systolic strain rate (p = 0.06) also tended to be lower in group I than group III. Group I also tended to have lower RV systolic strain (p = 0.09) and early diastolic strain rate (p = 0.049) and LV longitudinal systolic strain rate (p = 0.08) than group II. An increasing trend from group I to III was observed for RV lateral wall and septal systolic strain and strain rate (all p < 0.05). The LV but not RV size was significantly smaller in group I compared with group III (p < 0.05). Multiple regression identified duration of invasive ventilation (β = -0.66, p = 0.032) as an independent determinant of RV systolic strain after adjustment for perinatal risk factors. Conclusion: Impairment of RV myocardial deformation occurs in children with BPD, the magnitude of which is associated negatively with the duration of invasive ventilation.
- [Show abstract] [Hide abstract] ABSTRACT: Background: Myocardial fibrosis has been proposed to play an important pathogenetic role in left ventricular (LV) dysfunction in obesity. This study tested the hypothesis that calibrated integrated backscatter (cIB) as a marker of myocardial fibrosis is altered in obese adolescents and explored its associations with adiposity, LV myocardial deformation, and metabolic parameters. Methods/principal findings: Fifty-two obese adolescents and 38 non-obese controls were studied with conventional and speckle tracking echocardiography. The average cIB of ventricular septum and LV posterior wall was measured. In obese subjects, insulin resistance as estimated by homeostasis model assessment (HOMA-IR) and glucose tolerance were determined. Compared with controls, obese subjects had significantly greater cIB of ventricular septum (-16.8±7.8 dB vs -23.2±7.8 dB, p<0.001), LV posterior wall (-20.5±5.6 dBvs -25.0±5.1 dB, p<0.001) and their average (-18.7±5.7 dB vs -24.1±5.0 dB, p<0.001). For myocardial deformation, obese subjects had significantly reduced LV longitudinal systolic strain rate (SR) (p = 0.045) and early diastolic SR (p = 0.015), and LV circumferential systolic strain (p = 0.008), but greater LV longitudinal late diastolic SR (p<0.001), and radial early (p = 0.037) and late (p = 0.002) diastolic SR than controls. For the entire cohort, myocardial cIB correlated positively with body mass index (r = 0.45, p<0.001) and waist circumference (r = 0.45, p<0.001), but negatively with LV circumferential systolic strain (r = -0.23, p = 0.03) and systolic SR (r = -0.25, p = 0.016). Among obese subjects, cIB tended to correlate with HOMA-IR (r = 0.26, p = 0.07). Conclusion: Obese adolescents already exhibit evidence of increased myocardial fibrosis, which is associated with measures of adiposity and impaired LV circumferential myocardial deformation.
- [Show abstract] [Hide abstract] ABSTRACT: Detectable low circulating level of cardiac troponin T (cTnT) may reflect subclinical myocardial injury. We tested the hypothesis that circulating levels of hs-cTnT are altered in adults with repaired tetralogy of Fallot (TOF) and associated with ventricular volume load and function. Eighty-eight TOF patients and 48 controls were studied. Plasma hs-cTnT levels were determined using a highly sensitive assay (hs-cTnT). The right (RV) and left ventricular (LV) volumes and ejection fraction (EF) were measured using 3D echocardiography and, in 52 patients, cardiac magnetic resonance (CMR). The median (interquartile range) for male and female patients were 4.87 (3.83-6.62) ng/L and 3.11 (1.00-3.87) ng/L, respectively. Thirty percent of female but none of the male patients had increased hs-cTnT levels. Female patients with elevated hs-cTnT levels, compared to those without, had greater RV end-diastolic and end-systolic volumes and LV systolic dyssynchrony index (all p < 0.05). For patient cohort only, hs-cTnT levels correlated positively with CMR-derived RV end-diastolic volume and negatively with echocardiography-derived LV and RV EF (all p < 0.05). Multiple linear regression identified sex and RV EF as significant correlates of log-transformed hs-cTnT levels. Increased hs-cTnT levels occur in 30% of female patients after TOF repair, and are associated with greater RV volumes and worse RV EF.
- [Show abstract] [Hide abstract] ABSTRACT: Aims: This study aimed to explore the arterial-left ventricular (LV)-left atrial (LA) interaction in adolescents and young adults late after intervention for coarctation of the aorta (CoA) and interrupted aortic arch (IAA). Methods and results: Thirty-one (16 males) patients aged 23.4 ± 6.3, at 20.6 ± 5.2 years after intervention, and 31 controls were studied. Carotid arterial stiffness and intima-media thickness (IMT) and brachial-ankle pulse wave velocity were determined by radiofrequency-based echocardiography and oscillometry, respectively. Tissue Doppler and speckle tracking echocardiography (STE) were performed to assess, respectively, LV myocardial tissue velocities and linear and torsional deformation. Left atrial positive, negative, and total strain and strain rate at ventricular systole (aSRs), early diastole (aSRed), and atrial contraction (aSRac) were also determined using STE. Patients had significantly greater arterial stiffness and IMT than controls (all P < 0.05). Mitral annular systolic and diastolic velocities, LV longitudinal and radial strain and early diastolic strain rates, peak torsion and untwisting velocity, and LA peak positive and total strain, aSRs, aSRed, and aSRac were significantly lower in patients than in controls (all P < 0.05). Arterial stiffness correlated inversely with LV longitudinal strain and systolic and early diastolic strain rate (all P < 0.05), while LA total strain and aSRed were associated positively with LV diastolic annular velocity, longitudinal SRe, and peak untwisting velocity (all P < 0.05). Multiple linear regression further revealed arterial stiffness as an independent determinant of LA total strain (β = -1.3, P = 0.034). Conclusion: Our findings suggest impairment of arterial function and LV and LA mechanics in patients after CoA and IAA repair and implicate an abnormal arterial-LV-LA interaction.
- [Show abstract] [Hide abstract] ABSTRACT: Alteration of right ventricular (RV) function has been found in patients with pressure-loaded left ventricles due to systemic hypertension and aortic stenosis. We tested the hypothesis that RV mechanics are altered in adolescents and adults with repaired coarctation of the aorta (CoA). Twenty-eight (15 male) patients, aged 23.7 ± 6.5 years, and 28 (14 male) controls were studied. M-mode, tissue Doppler imaging, and speckle tracking echocardiography were performed to assess, respectively, LV mass and RV wall thickness, RV myocardial tissue velocities, and deformation. Systolic (P = 0.14) and diastolic (P = 0.32) blood pressures were similar between patients and controls. Compared with controls, patients had significantly greater LV mass (P = 0.016) and RV anterior wall thickness (P = 0.012). Tricuspid annular systolic (P < 0.001) and early diastolic (P < 0.001) velocities, isovolumic acceleration (P = 0.004), global RV systolic longitudinal strain (P = 0.03), systolic strain rate (P = 0.012), and early (P = 0.021) and late (P = 0.012) diastolic strain rates were significantly lower in patients than controls. Patients with an associated ventricular septal defect (n = 6) requiring closure compared to those without had even lower tricuspid annular systolic (P = 0.01) and early diastolic (P = 0.041) velocities. Left ventricular mass correlated negatively with RV systolic strain rate (r = -0.27, P = 0.045) and tricuspid annular early diastolic velocity (r = -0.40, P = 0.002), while RV anterior wall thickness correlated negatively with tricuspid annular systolic (r = -0.42, P = 0.002) and late diastolic (r = -0.40, P = 0.003) velocities, and positively with e/a ratio (r = 0.31, P = 0.024). RV systolic and diastolic mechanics are impaired in patients late after repair of CoA and related to increased LV mass and RV thickness. © 2014, Wiley Periodicals, Inc.
- [Show abstract] [Hide abstract] ABSTRACT: We assessed the left ventricular (LV) contractile reserve in young adults with repaired coarctation of the aorta and interrupted aortic arch by determination of LV force-frequency relation (FFR). Eighteen (7 men) patients aged 24.2 ± 5.4 years and 20 (9 men) healthy controls were studied. Blood pressures in the right arm were measured by oscillometry. Transmitral early (E) and late (A) diastolic velocities, tissue Doppler-derived mitral annular systolic (sm), early diastolic (em) and late diastolic (am) velocities, and myocardial isovolumic acceleration (IVA) were measured. The LV FFR and average slope were derived from the IVA measured at different heart rates during supine bicycle exercise. Blood pressures at rest were similar between patients and controls (all p >0.05). At baseline, patients compared with controls had significantly greater E velocity, E/A and E/em ratios, and lower sm and em velocities (all p <0.05) but similar IVA (p = 0.18). At submaximal exercise, diastolic (p = 0.001) and mean (p = 0.003) blood pressures became significantly higher in patients than controls, sm (p = 0.001) and em (p <0.001) velocities remained reduced, whereas the IVA became lower (p <0.001). The weighted average FFR was flattened (p <0.001), and average FFR slope was lower (p <0.001) in patients compared with controls. The average FFR slope correlated negatively with the magnitude of exercise-induced increase in systolic (r = -0.32, p = 0.050), mean (r = -0.41, p = 0.011), and diastolic (r = -0.40, p = 0.013) blood pressures. In conclusion, young adults after coarctation of the aorta and interrupted aortic arch repair exhibit reduced LV contractile reserve, which is related to the blood pressure response during exercise stress. Copyright © 2014 Elsevier Inc. All rights reserved.
- [Show abstract] [Hide abstract] ABSTRACT: Background: Iron overload cardiomyopathy that prevails in some forms of hemosiderosis is caused by excessive deposition of iron into the heart tissue and ensuing damage caused by a raise in labile cell iron. The underlying mechanisms of iron uptake into cardiomyocytes in iron overload condition are still under investigation. Both L-type calcium channels (LTCC) and T-type calcium channels (TTCC) have been proposed to be the main portals of non-transferrinic iron into heart cells, but controversies remain. Here, we investigated the roles of LTCC and TTCC as mediators of cardiac iron overload and cellular damage by using specific Calcium channel blockers as potential suppressors of labile Fe(II) and Fe(III) ingress in cultured cardiomyocytes and ensuing apoptosis.
- [Show abstract] [Hide abstract] ABSTRACT: Kawasaki disease (KD), an acute vasculitis that primarily affects young children, is the most common acquired paediatric cardiovascular disease in developed countries. While sequelae of arterial inflammation in the acute phase of KD are well documented, its late effects on vascular health are increasingly unveiled. Late vascular dysfunction is characterized by structural alterations and functional impairment in term of arterial stiffening and endothelial dysfunction and shown to involve both coronary and systemic arteries. Further evidence suggests that continuous low grade inflammation and ongoing active remodeling of coronary arterial lesions occur late after acute illness and may play a role in structural and functional alterations of the arteries. Potential importance of genetic modulation on vascular health late after KD is implicated by associations between mannose binding lectin and inflammatory gene polymorphisms with severity of peripheral arterial stiffening and carotid intima-media thickening. The changes in cholesterol and lipoproteins levels late after KD further appear similar to those proposed to be atherogenic. While data on adverse vascular health are less controversial in patients with persistent or regressed coronary arterial aneurysms, data appear conflicting in individuals with no coronary arterial involvements or only transient coronary ectasia. Notwithstanding, concerns have been raised with regard to predisposition of KD in childhood to accelerated atherosclerosis in adulthood. Until further evidence-based data are available, however, it remains important to assess and monitor cardiovascular risk factors and to promote cardiovascular health in children with a history of KD in the long term.
- [Show abstract] [Hide abstract] ABSTRACT: Objective This review aims to provide an overview of conventional and novel indices used in clinical and research arenas for evaluation of right ventricular (RV) function in congenital heart diseases with a dual-chambered circulation. Data sources Articles cited in this review were selected using PubMed search of publications in English with no date limits. The search terms included "echocardiography", "right ventricle", "RV function", "cardiac function", and "congenital heart disease". Key references were also searched for additional publications. Study selection Articles related to description of echocardiographic techniques in the evaluation of subpulmonary or systemic RV function and their applications in congenital cardiac malformations were retrieved and reviewed. Results Three approaches have been used to evaluate subpulmonary and systemic RV function: (1) assessment of changes in RV size in the cardiac cycle, (2) determination of Doppler-derived velocities and systolic and diastolic time intervals, and (3) quantification of myocardial velocities and deformation. Conclusions Conventional and novel echocardiographic techniques enable the evaluation of subpulmonary and systemic RV function. Novel echocardiographic techniques have further allowed quantification of RV volumes and direct interrogation of myocardial deformation. These new techniques show promise in a more comprehensive evaluation beyond "eye-balling" of RV function in the growing population of adolescent and adult congenital heart patients.
- [Show abstract] [Hide abstract] ABSTRACT: Background Differences in systemic venous flow dynamics and energy losses exist in various Fontan-type procedures, which may affect atrial and ventricular filling. The aim of this study was to test the hypothesis that atrial and ventricular mechanics differ between two types of Fontan procedures, atriopulmonary connection (APC) and extracardiac conduit, which have distinctly different systemic venous hemodynamics. Methods This was a cross-sectional, case-control study of 28 Fontan patients (13 with APC, 15 with extracardiac conduit) aged 19.8 ± 6.5 years and 26 healthy controls. Atrial and systemic ventricular myocardial deformation was determined using speckle-tracking echocardiography, while ventricular volumes and systolic dyssynchrony index were assessed using three-dimensional echocardiography. Results Compared with controls, patients had significantly lower values of global ventricular longitudinal, circumferential, and radial systolic strain in all three directions, reduced systolic and early diastolic strain rates (SRs) in more than one dimension, lower ejection fractions, and worse ventricular dyssynchrony. For atrial deformation, patients had lower global and positive strain and conduit and reservoir SRs and delayed electromechanical coupling. Among patients, those with APC had significantly lower ventricular longitudinal strain and early diastolic SRs, worse ventricular dyssynchrony, and reduced atrial positive and negative strain and conduit and active contractile SRs. Atrial global strain (r = 0.60, P = .001) and conduit SR (r = 0.49, P = .008) correlated positively with systemic ventricular early diastolic SR. Conclusions Atrial and ventricular mechanics are impaired in patients after Fontan-type operation, which is worse with APC than extracardiac conduit.
- [Show abstract] [Hide abstract] ABSTRACT: This study sought to explore right (RV) and left ventricular (LV) mechanics and ventricular-ventricular interaction in adolescents and young adults late after percutaneous balloon pulmonary valvoplasty (PBPV) for valvar pulmonary stenosis (PS). Potential late effects of PS despite PBPV on cardiac mechanics have not been well defined. Thirty-one patients aged 20.2 ± 7.6 years were studied at 18 ± 6 years after PBPV. Ventricular myocardial deformation was determined using speckle tracking echocardiography, while RV and LV volumes and ejection fraction as well as LV systolic dyssynchrony index were assessed by three-dimensional echocardiography. The results were compared with those of 30 controls. Pulmonary regurgitation, mostly trivial to mild, was present in 90% (28/31) of patients. Compared with controls, patients had significantly greater RV end-diastolic (P < 0.001), RV end-systolic (P < 0.001), and LV end-systolic (P = 0.04) volumes as well as lower LV ejection fraction (P < 0.001). For deformation, patients had significantly reduced RV longitudinal systolic strain (P = 0.004), decreased LV circumferential systolic strain (P < 0.001), and strain rate (P = 0.001) as well as greater LV mechanical dyssynchrony (P < 0.001). In patients, RV end-diastolic and end-systolic volumes correlated with LV circumferential strain (r = -0.47, P = 0.008 and r = -0.36, P = 0.049, respectively) and dyssynchrony (r = 0.53, P = 0.002 and r = 0.49, P = 0.005, respectively). Patients who had PBPV at age ≤1 year had ventricular deformation indices similar to those who had interventions beyond 1 year. Impaired RV and LV mechanics and adverse ventricular-ventricular interaction occur in adolescents and young adults late after balloon valvoplasty for isolated valvar PS.
- [Show abstract] [Hide abstract] ABSTRACT: Iron may damage sarcomeric proteins through oxidative stress. We explored the left ventricular (LV) torsional mechanics in patients with beta-thalassaemia major and its relationship to myocardial iron load. Using HL-1 cell and B6D2F1 mouse models, we further determined the impact of iron load on proteolysis of the giant sarcomeric protein titin.Methods and results: In 44 thalassaemia patients aged 25 +/- 7 years and 38 healthy subjects, LV torsion and twisting velocities were determined at rest using speckle tracking echocardiography. Changes in LV torsional parameters during submaximal exercise testing were further assessed in 32 patients and 17 controls. Compared with controls, patients had significantly reduced LV apical rotation, torsion, systolic twisting velocity, and diastolic untwisting velocity. T2* cardiac magnetic resonance findings correlated with resting diastolic untwisting velocity. The increments from baseline and resultant LV torsion and systolic and diastolic untwisting velocities during exercise were significantly lower in patients than controls. Significant correlations existed between LV systolic torsion and diastolic untwisting velocities in patients and controls, both at rest and during exercise. In HL-1 cells and ventricular myocardium of B6D2F1 mice overloaded with iron, the titin-stained pattern of sarcomeric structure became disrupted. Gel electrophoresis of iron-overloaded mouse myocardial tissue further showed significant decrease in the amount of titin isoforms and increase in titin degradation products. Resting and dynamic LV torsional mechanics is impaired in patients with beta-thalassaemia major. Cell and animal models suggest a potential role of titin degradation in iron overload-induced alteration of LV torsional mechanics.
- [Show abstract] [Hide abstract] ABSTRACT: 22q11.2 deletion syndrome (22q11.2DS) is a multi-systemic disorder with high phenotypic variability. Under-diagnosis in adults is common and recognition of facial dysmorphic features can be affected by age and ethnicity. This study aims to determine the prevalence of undiagnosed 22q11.2DS in adult Chinese patients with conotruncal anomalies and to delineate their facial dysmorphisms and extra-cardiac manifestations. We recruited consecutively 156 patients with conotruncal anomalies in an adult congenital heart disease (CHD) clinic in Hong Kong and screened for 22q11.2DS using fluorescence-PCR and fluorescence in-situ hybridization. Assessment for dysmorphic features was performed by a cardiologist at initial screening and then by a clinical geneticist upon result disclosure. Clinical photographs were taken and childhood photographs collected. Eighteen patients (11.5%) were diagnosed with 22q11.2DS, translating into 1 previously unrecognized diagnosis of 22q11.2DS in every 10 adult patients with conotruncal anomalies. While dysmorphic features were detected by our clinical geneticist in all patients, only two-thirds were considered dysmorphic by our cardiologist upon first assessment. Evolution of facial dysmorphic features was noted with age. Extra-cardiac manifestations included velopharyngeal incompetence or cleft palate (44%), hypocalcemia (39%), neurodevelopmental anomalies (33%), thrombocytopenia (28%), psychiatric disorders (17%), epilepsy (17%) and hearing loss (17%). We conclude that under-diagnosis of 22q11.2DS in Chinese adults with conotruncal defects is common and facial dysmorphic features may not be reliably recognized in the setting of adult CHD clinic, referral for genetic evaluation and molecular testing for 22q11.2DS should be offered to patients with conotruncal defects.
- [Show abstract] [Hide abstract] ABSTRACT: Ventricular diastolic dysfunction in patients with repaired tetralogy of Fallot (TOF) may affect atrial mechanics. This study aimed to explore right atrial (RA) and left atrial (LA) mechanics in repaired TOF patients and their relationship with ventricular diastolic function. Fifty-four patients (36 males), aged 17.8 ± 8.3 years, who had undergone TOF repair at 3.9 ± 3.3 years and 40 healthy subjects aged 16.9 ± 6.3 years (P = 0.57) were studied. Right and LA peak positive, peak negative, and total strain, strain rate at ventricular systole (SRs ), early diastole (SRed ), and atrial contraction (SRac ), and electromechanical delay were determined using speckle tracking echocardiography (STE). Ventricular diastolic function was assessed by tissue Doppler imaging and STE. Ventricular volumes and pulmonary regurgitant volume were derived from 3D echocardiography. Compared with controls, patients had significantly lower RA and LA peak positive and total strain, SRs , SRed , and SRac (all P < 0.001). The timing of RA (178 ± 33 msec vs. 152 ± 17 msec, P < 0.001) and LA (170 ± 32 msec vs. 152 ± 24 msec, P = 0.006) electromechanical coupling (EMC) was significantly longer in patients than in controls. The RA total strain, SRs , SRed , SRac , and EMC correlated positively with corresponding LA parameters (all P < 0.001). The RA and LA total strain and SRed were associated positively with diastolic annular velocities and strain rates of respective ventricles (all P < 0.05). The LA SRed correlated negatively with pulmonary regurgitant volume (r = -0.33, P = 0.016) and RV end-diastolic volume (r = -0.33, P = 0.015). Mechanics of both atria are impaired in patients after repair of TOF and are associated with diastolic performance of the respective ventricles.
- [Show abstract] [Hide abstract] ABSTRACT: Background The clinical relevance of evaluating right ventricular (RV) myocardial deformation in congenital heart disease is increasingly recognized. The aim of this study was to explore, using three-dimensional (3D) speckle-tracking echocardiography, RV mechanics in terms of 3D global area strain and mechanical dyssynchrony in adults with repaired tetralogy of Fallot. Methods Twenty patients (12 men) aged 24.7 ± 8.6 years and 22 age-matched controls (11 men) were studied. Global RV peak area strain and area strain–derived systolic dyssynchrony index (SDI) were determined using 3D speckle-tracking echocardiography. RV end-diastolic volume and end-systolic volume, ejection fraction (EF), and pulmonary regurgitation fraction were measured in patients using cardiac magnetic resonance. Results Coefficients of variation for intraobserver and interobserver measurements of RV global area strain were 6.1% and 7.9%, respectively, and those for SDI were 7.6% and 10.1%, respectively. Compared with controls, patients had significantly lower global area strain (P = .005) and greater SDI (P = .008). The prevalence of RV mechanical dyssynchrony (SDI > control mean + 2 SDs) in patients was 30%. In patients, global area strain correlated inversely with SDI (r = −0.42, P = .04), RV end-diastolic volume (r = −0.48, P = .032), and RV end-systolic volume (r = −0.48, P = .031) and positively with EF (r = −0.51, P = .02), while RV SDI correlated positively with RV end-systolic volume (r = 0.55, P = .012), pulmonary regurgitation fraction (r = 0.54, P = .031), and QRS duration (r = 0.51, P = .022) and negatively with RV EF (r = −0.62, P = .004). Multivariate analysis showed that RV EF (β = 0.22, P = .048) was a significant correlate of global area strain in patients. Conclusions In adults after tetralogy of Fallot repair, 3D RV deformation is impaired in association with RV dyssynchrony, volume overloading, and reduced EF.
- [Show abstract] [Hide abstract] ABSTRACT: Background: Increased circulating endothelial microparticles (EMPs) have been shown to associate with endothelial dysfunction. We explored the effect of iron on EMP generation by human umbilical vein endothelial cells (HUVECs) and the potential protective effect of carvedilol. Methods: FeCl 3 was added to HUVEC culture. Iron entry into cells was monitored using fluorescent microscopic imaging, while the quantity of EMPs that was released was determined by flow cytometry. The apoptosis of HUVECs was assessed by annexin V/propidium iodide assay and caspase-3 expression. Membrane bleb formation was visualized using electron microscopy. Intracellular production of reactive oxygen species (ROS) was also monitored. The effects of beta-blockers, carvedilol and propranolol on these processes were determined by co-incubation in a dose-dependent manner. Iron entry into HUVECs was not blocked by either beta-blocker. Iron induced the generation of EMPs, the formation of membrane blebs, the apoptosis of HUVECs and the production of ROS, each in a dose-dependent manner. Carvedilol, but not propranolol, ameliorated all of these processes. Results: Our result indicates that iron induces EMP generation and apoptosis of endothelial cells in association with increased oxidative stress. Conclusion: The protective effects of carvedilol, via its antioxidant effect, may have therapeutic potential in patients with iron overload.
- [Show abstract] [Hide abstract] ABSTRACT: Significant improvement in survival of children with congenital cardiac malformations has resulted in an increasing population of adolescent and adult patients with congenital heart disease. Of the long-term cardiac problems, ventricular dysfunction remains an important issue of concern. Despite corrective or palliative repair of congenital heart lesions, the right ventricle, which may be the subpulmonary or systemic ventricular chamber, and the functional single ventricle are particularly vulnerable to functional impairment. Regular assessment of cardiac function constitutes an important aspect in the long-term follow up of patients with congenital heart disease. Echocardiography remains the most useful imaging modality for longitudinal monitoring of cardiac function. Conventional echocardiographic assessment has focused primarily on quantification of changes in ventricular size and blood flow velocities during the cardiac cycles. Advances in echocardiographic technologies including tissue Doppler imaging and speckle tracking echocardiography have enabled direct interrogation of myocardial deformation. In this review, the issues of ventricular dysfunction in congenital heart disease, conventional echocardiographic and novel myocardial deformation imaging techniques, and clinical applications of these techniques in the functional assessment of congenital heart disease are discussed.
- [Show abstract] [Hide abstract] ABSTRACT: We sought to determine the arterial mechanics at rest and during exercise in adolescents and young adults with complete transposition of the great arteries after arterial switch operation and their relations with neoaortic complications. Thirty patients (22 men) aged 16.2 ± 2.1 years and 22 controls (15 men) were studied. Central and peripheral arterial pulse wave velocities, carotid and radial augmentation indices, and central systolic blood pressure (cSBP) were determined by oscillometry and applanation tonometry, whereas arterial dimensions were measured by 2-dimensional echocardiography. Arterial strain, distensibility, and stiffness were determined at rest and during supine bicycle exercise testing. At rest, patients had significantly higher heart-carotid pulse wave velocity, carotid and radial augmentation indices, and cSBP than controls. At rest and during submaximal exercise, patients had significantly lower aortic strain and distensibility, greater aortic and carotid stiffness, and higher SBP than controls. Dilated aortic sinus found in 23 (76.7%) patients was associated with lower aortic distensibility, greater aortic stiffness, and higher cSBP at rest and lower aortic distensibility and strain at submaximal exercise. Significant aortic regurgitation found in 20% (6 of 30) of patients was associated with significantly higher neoaortic z scores. Multivariate analysis identified aortic stiffness at rest (β = 0.46, p = 0.003) and age at operation (β = 0.44, p = 0.004) as significant determinants of aortic sinus z scores. In conclusion, altered mechanics of the central arteries are present at rest and during exercise in adolescents and young adults after arterial switch operation. These findings may have important implications on progression of neoaortic root dilation, exercise recommendations, and medical therapy.
Queen Mary HospitalHong Kong, Hong Kong
The University of Hong Kong
Hong Kong, Hong Kong
- Department of Paediatrics and Adolescent Medicine
Hong Kong Hospital AuthorityHong Kong, Hong Kong