Pressure-Strain Loops, a Novel Non-invasive Approach for Assessment of Children with Cardiomyopathy.

Non-invasive myocardial work (MW) by left ventricular (LV) pressure-strain loops (PSL) is a novel method for assessing myocardial function while adjusting for afterload, yet pediatric data remain lacking. The aims of this study were to investigate the different patterns of LV PSL and non-invasive MW in pediatric patients with hypertrophic (HCM) and dilated cardiomyopathy (DCM) and their association with exercise tolerance. We included 110 pediatric subjects (mean age, 13 ± 4 years, 35 DCM, 40 HCM, and 35 healthy controls). Standard and speckle-tracking echocardiography were performed. LV PSLs were generated, and global work index (GWI), MW efficiency (GWE), constructive work (GCW), and wasted work (GWW) were compared between groups. Regression analysis was used to assess the influence of ventricular function, dimensions, wall thickness, and wall stress on MW and to predict the association between MW and VO2 max as a surrogate of exercise capacity. Patients with DCM had significantly lower GWI compared to controls (GWI 479.6 ± 263.0 vs 1610.1 ± 211.0, P < 0.005). GWE was significantly reduced in DCM (79.3 ± 7.9 vs 95.2 ± 1.3, P < 0.005) due to significantly reduced GCW and increased GWW. HCM patients had significant reduction in GWI and GWE from normal (1237.7 ± 449.1 vs 1610.1 ± 211.0, P = 0.001 and 89.6 ± 4.9 vs 95.2 ± 1.3, P < 0.005, respectively), although less severe than with DCM. In a multivariate regression analysis, GWE had the highest association with VO2 max in both cohorts (DCM: ß = 0.68, P = 0.001, HCM: ß = 0.71, P = 0.007). Non-invasively assessed myocardial work and LV PSLs provide novel insights into the mechanisms of dysfunction in pediatric patients with cardiomyopathy with good prediction of clinical status and thus hold promise to further explore myocardial mechanistic with clinical relevance in different disease entities.

Parameters of Right Ventricular Function Reveal Ventricular-Vascular Mismatch as Determined by Right Ventricular Stroke Work versus Pulmonary Vascular Resistance in Children with Pulmonary Hypertension.

BACKGROUND: Right ventricular (RV) failure, a determinant of outcomes in pulmonary hypertension (PH), occurs when the right ventricle cannot compensate for increased afterload. The authors showed that RV stroke work (RVSW) can be estimated in children with PH as the product of stroke volume and RV pressure and is related to adverse outcomes. The aim of this study was to test the hypothesis that ventricular-vascular (VV) mismatch (high afterload and low RVSW) is associated with echocardiographic measures of RV performance and adverse outcomes. METHODS: Invasive hemodynamic data and concurrent echocardiograms were reviewed. Fifty subjects with PH were included. Four groups were created by dividing the patients using median RVSW and median pulmonary vascular resistance. For each group, tricuspid annular plane systolic excursion, fractional area change, myocardial performance index, and anterior RV wall thickness were determined. Both major (i.e., death) and minor (i.e., worsening World Health Organization class) clinical outcomes were tabulated. Groups were compared using the Kruskal-Wallis or Fisher exact test. RESULTS: Patients in the high pulmonary vascular resistance/low RVSW cohort (VV mismatch) had the worst RV dysfunction: median tricuspid annular plane systolic excursion, 0.8 cm (interquartile range, 0.7-0.8 cm; P = .0002); median fractional area change, 0.29% (interquartile range, 0.27%-0.30%; P = .004); median myocardial performance index, 0.622 (interquartile range, 0.548-0.789; P = .0004). This group had the highest incidence of adverse outcomes: major events in 40%, minor events in 80%, and syncope in 60%. CONCLUSION: VV mismatch in pediatric PH can be assessed using RVSW and pulmonary vascular resistance and is associated with RV performance and adverse events. RVSW increases in compensated high-afterload states and falls as the right ventricle fails to meet increased load; thus, VV matching status may be a sensitive predictor of outcomes in pediatric PH.

Retrospective Comparison of the Supported and Unsupported Bovine Jugular Vein Conduit in Children.

BACKGROUND: Bovine jugular vein (BJV) conduits are commonly used for pulmonary valve replacement in pediatric patients. They are available in supported (sBJV) and unsupported (uBJV) versions. The purpose of this study was to compare outcomes of sBJV and uBJV conduits. METHODS: In this single-center retrospective review of patients younger than 18 years undergoing BJV placement (2009 to 2017), blinded cardiologists reviewed postoperative 6-, 12-, 24-, 36-month, and the most recent echocardiogram before any valve-related event or death. Outcomes assessed included conduit stenosis (m/s), regurgitation (none to mild vs moderate to severe) and right ventricular function (normal vs abnormal). Cox proportional models and Kaplan-Meier analyses were performed. RESULTS: BJV conduits (N = 109) were placed (39 supported, 70 unsupported) in 101 patients. Patient characteristics and conduit size were not different between cohorts. sBJV had more stenosis at 6 and 12 months (p = 0.02 and p = 0.03), but Vmax in both groups was mild (≤2 m/s). A greater proportion of uBJV had moderate to severe regurgitation at 12 months compared with sBJV (p = 0.03). Right ventricular function did not differ at any time point. On last follow-up echocardiogram, sBJV conduits had higher gradients (p = 0.01). This was not associated with increased intervention or replacement. Freedom from replacement or intervention did not differ between valve types (median follow-up, 3.6 years). There was a 9% incidence of endocarditis at median follow-up 2.4 years. Seventy percent of cases with endocarditis were managed medically. CONCLUSIONS: There were no clinically significant echocardiographic or outcome differences between sBJV and uBJV conduits. We identified a relatively high incidence of endocarditis, which is consistent with prior reports.

Metabolomic Fingerprinting of Infants Undergoing Cardiopulmonary Bypass: Changes in Metabolic Pathways and Association With Mortality and Cardiac Intensive Care Unit Length of Stay.

Background Mortality for infants undergoing complex cardiac surgery is >10% with a 30% to 40% risk of complications. Early identification and treatment of high-risk infants remains challenging. Metabolites are small molecules that determine the minute-to-minute cellular phenotype, making them ideal biomarkers for postsurgical monitoring and potential targets for intervention. Methods and Results We measured 165 serum metabolites by tandem mass spectroscopy in infants ≤120 days old undergoing cardiopulmonary bypass. Samples were collected prebypass, during rewarming, and 24 hours after surgery. Partial least squares-discriminant analysis, pathway analysis, and receiver operator characteristic curve analysis were used to evaluate changes in the metabolome, assess altered metabolic pathways, and discriminate between survivors/nonsurvivors as well as upper/lower 50% intensive care unit length of stay. Eighty-two infants had preoperative samples for analysis; 57 also had rewarming and 24-hour samples. Preoperation, the metabolic fingerprint of neonates differed from older infants ( R2=0.89, Q2=0.77; P<0.001). Cardiopulmonary bypass resulted in progressive, age-independent metabolic disturbance ( R2=0.92, Q2=0.83; P<0.001). Multiple pathways demonstrated changes, with arginine/proline ( P=1.2×10-35), glutathione ( P=3.3×10-39), and alanine/aspartate/glutamate ( P=1.4×10-26) metabolism most affected. Six subjects died. Nonsurvivors demonstrated altered aspartate ( P=0.007) and nicotinate/nicotinamide metabolism ( P=0.005). The combination of 24-hour aspartate and methylnicotinamide identified nonsurvivors versus survivors (area under the curve, 0.86; P<0.01), as well as upper/lower 50% intensive care unit length of stay (area under the curve, 0.89; P<0.01). Conclusions The preoperative metabolic fingerprint of neonates differed from older infants. Large metabolic shifts occurred after cardiopulmonary bypass, independent of age. Nonsurvivors and subjects requiring longer intensive care unit length of stay showed distinct changes in metabolism. Specific metabolites, including aspartate and methylnicotinamide, may differentiate sicker patients from those experiencing a more benign course.

Strain and Rotational Mechanics in Children With Single Left Ventricles After Fontan.

BACKGROUND: Left ventricular (LV) mechanics in patients with different single morphologic LV subtypes, including tricuspid atresia, double-inlet left ventricle, and pulmonary atresia with intact ventricular septum, remain poorly studied. Given that histologic studies indicate differences in LV myocardial fiber orientation, we hypothesized that this may result in altered LV mechanics. The aim of this study was to evaluate the influence of LV morphology on LV mechanics. METHODS: Fifty-two children with single left ventricles after Fontan operation and age-matched control subjects were prospectively enrolled. Using two-dimensional speckle-tracking echocardiography, longitudinal strain was measured in the four-, three-, and two-chamber long-axis planes, and circumferential strain was measured at the basal, mid, and apical short-axis planes. Apical and basal rotation were measured, and twist and torsion were calculated. We compared strain and rotational mechanics in cases versus control subjects and among LV subtypes. RESULTS: Compared with control subjects, subjects with single left ventricles had similar LV end-diastolic dimensions but significantly decreased ejection fractions. The single left ventricle cohort had normal global longitudinal strain (P = .20) but lower basal mean circumferential strain (P < .0001). Single left ventricle subjects had higher apical rotation (P = .0001) but decreased basal rotation (P = .0007); there was no difference in twist but increased torsion (P = .001). LV subtypes had different four-chamber (P = .01), two-chamber (P = .006), and global longitudinal strain (P = .01), lowest in the pulmonary atresia with intact ventricular septum subtype. CONCLUSIONS: Longitudinal LV strain was preserved in children with single left ventricles after Fontan. A pattern of reduced basal circumferential strain and rotation with an increase in apical rotation and torsion in the single left ventricle cohort may be related to differences in myofiber orientation, increased fibrosis, and the impact of altered loading conditions throughout palliation. Decreased longitudinal strain in the pulmonary atresia with intact ventricular septum group may also reflect detrimental interventricular interactions.

Worsening in Longitudinal Strain and Strain Rate Anticipates Development of Pediatric Transplant Coronary Artery Vasculopathy as Soon as One Year Following Transplant.

Transplant coronary artery vasculopathy (TCAV) following orthotopic heart transplantation (OHT) continues to be the primary reason for late graft failure in children. The current gold standard of diagnosis of TCAV is coronary angiography with or without intravascular ultrasound. This study investigates the longitudinal use of speckle-tracking echocardiographic strain imaging as an early non-invasive marker to screen for development of TCAV. Echocardiograms from patients who underwent OHT between 2006 and 2010 at Children's Hospital Colorado (n = 50) were retrospectively assessed. Studies were evaluated at baseline (within a month of transplant), then at each annual clinical follow-up for peak longitudinal (LS) and circumferential (CS) strain, systolic strain rate, and diastolic strain rate using Siemens Velocity Vector Imaging software. Comparisons were made between subjects who did and did not develop TCAV. Mean time to TCAV diagnosis following OHT was 3.2 years (range 1-5.1 years). One year after transplant, significant differences were seen between groups in LS (non-TCAV mean -19.6%, TCAV mean -17.3%, p = 0.03) and longitudinal strain rate (non-TCAV mean -1.7%/s, TCAV mean -1.4%/s, p = 0.04). These differences persisted in subsequent years. Differences in LS preceded the catheterization-based diagnosis of TCAV in pediatric heart recipients and were noted as early as one year post transplant. Additionally, within-subject LS changes may have utility as a non-invasive screening tool to predict those patients at increased risk for development of TCAV.

Quantification of Left Ventricular Shape Differentiates Pediatric Pulmonary Hypertension Subjects From Matched Controls.

Changes in left ventricle (LV) shape are observed in patients with pulmonary hypertension (PH). Quantification of ventricular shape could serve as a tool to noninvasively monitor pediatric patients with PH. Decomposing the shape of a ventricle into a series of components and magnitudes will facilitate differentiation of healthy and PH subjects. Parasternal short-axis echo images acquired from 53 pediatric subjects with PH and 53 age and sex-matched normal control subjects underwent speckle tracking using Velocity Vector Imaging (Siemens) to produce a series of x,y coordinates tracing the LV endocardium in each frame. Coordinates were converted to polar format after which the Fourier transform was used to derive shape component magnitudes in each frame. Magnitudes of the first 11 components were normalized to heart size (magnitude/LV length as measured on apical view) and analyzed across a single cardiac cycle. Logistic regression was used to test predictive power of the method. Fourier decomposition produced a series of shape components from short-axis echo views of the LV. Mean values for all 11 components analyzed were significantly different between groups (p < 0.05). The accuracy index of the receiver operator curve was 0.85. Quantification of LV shape can differentiate normal pediatric subjects from those with PH. Shape analysis is a promising method to precisely describe shape changes observed in PH. Differences between groups speak to intraventricular coupling that occurs in right ventricular (RV) overload. Further analysis investigating the correlation of shape to clinical parameters is underway.

Lower spatial QRS-T angle rules out sustained ventricular arrhythmias in children with hypertrophic cardiomyopathy.

Introduction The spatial peaks QRS-T angle accurately distinguishes children with hypertrophic cardiomyopathy from their healthy counterparts. The spatial peaks QRS-T angle is also useful in risk stratification for ventricular arrhythmias. We hypothesised that the spatial peaks QRS-T angle would be useful for the prediction of ventricular arrhythmias in hypertrophic cardiomyopathy patients under 23 years of age. METHODS: Corrected QT interval and spatial peaks QRS-T angles were retrospectively assessed in 133 paediatric hypertrophic cardiomyopathy patients (12.4±6.6 years) with versus without ventricular arrhythmias of 30 seconds or longer. Significance, positive/negative predictive values, and odds ratios were calculated based on receiver operating characteristic curve cut-off values. RESULTS: In total, 10 patients with ventricular arrhythmias were identified. Although the corrected QT interval did not differentiate those with versus without ventricular arrhythmias, the spatial peaks QRS-T angle did (151.4±19.0 versus 116.8±42.6 degrees, respectively, p<0.001). At an optimal cut-off value (124.1 degrees), the positive and negative predictive values of the spatial peaks QRS-T angle were 15.4 and 100.0%, respectively, with an odds ratio of 25.9 (95% CI 1.5-452.2). CONCLUSION: In children with hypertrophic cardiomyopathy, the spatial peaks QRS-T angle is associated with ventricular arrhythmia burden with high negative predictive value and odds ratio.

Longitudinal Strain and Strain Rate Abnormalities Precede Invasive Diagnosis of Transplant Coronary Artery Vasculopathy in Pediatric Cardiac Transplant Patients.

Transplant coronary artery vasculopathy (TCAV) is the primary cause of late graft loss in pediatric heart transplant recipients. TCAV is diagnosed using angiography or intravascular ultrasound; however, noninvasive methods remain elusive. We sought to define patterns of myocardial mechanics in patients with TCAV and to determine whether this can detect TCAV before invasive methods. In this retrospective study, we queried our heart transplant database to identify all recipients with TCAV since 2006 (n = 41). Echoes were reviewed from the last normal catheterization and at TCAV diagnosis, and from time-matched transplant controls (n = 33) without TCAV. Peak global circumferential and longitudinal strain and systolic and diastolic strain rate (SSR and DSR) of the left ventricle were derived using velocity vector imaging. T tests were used to compare both groups longitudinally and between groups at both time points. Longitudinal strain, SSR, and DSR were diminished in the TCAV group compared to the transplant control group at both time points. No differences were found across time points in either group. Retrospective modeling using a longitudinal strain cutoff of 15 % on echoes 2 years prior to TCAV diagnosis predicted development or exclusion of TCAV with sensitivity of 53 %, specificity of 89 % with an area under the curve of 0.8. Decreases in longitudinal strain measurements demonstrate that alterations in myocardial mechanics occur in patients with TCAV at least 2 years prior to invasive diagnosis. These early changes may be due to microvascular disease. This modality could aid in earlier treatment and intervention for this challenging problem .

Repolarization Vector Magnitude Differentiates Kawasaki Disease from Normal Children.

INTRODUCTION: Kawasaki disease (KD) is the leading cause of acquired heart disease in children. The 12-lead electrocardiogram (ECG) changes in patients during the acute phase of KD include flattened T waves and prolonged corrected QT intervals (QTc). We set out to determine the 12-lead ECG and vectorcardiography predictors for identification of patients with KD and which of these predictors would be clinically useful for early identification of those with coronary artery anomalies (CAA). METHODS: A blinded, retrospective case-control study of patients with KD and age-matched controls was performed. Deep Q waves, QTc, spatial QRS-T angles, and T-wave vector magnitude (root mean square of the T wave, RMS-T) were assessed. Comparisons between groups were performed to test for significant differences. RESULTS: Fifty patients with KD (mean age 3.1 ± 3.1 years, 26% female) were compared to 50 previously healthy control patients (mean age 3.8 ± 2.9 years, 44% female). Of the KD patients, 32 (64%) were diagnosed as incomplete KD and 28 (56%) of them had CAA. When compared to the control group, KD patients had abnormal Q waves (72% vs 44% P = 0.005), shorter QTc values (395.1 ± 24.7 ms vs 410.4 ± 34.7 ms, P = 0.013), and lower RMS-T (0.42 ± 0.02 mV vs 0.63 ± 0.03 mV P < 0.001), respectively. Incomplete KD was also discriminated from controls by the same parameters. No differences were noted between KD patients with versus without CAA. CONCLUSION: The RMS-T differentiates complete and incomplete KD from controls. KD patients with CAA were not differentiated from those without CAA.

Guidelines for the Use of Echocardiography in the Evaluation of a Cardiac Source of Embolism.

Embolism from the heart or the thoracic aorta often leads to clinically significant morbidity and mortality due to transient ischemic attack, stroke or occlusion of peripheral arteries. Transthoracic and transesophageal echocardiography are the key diagnostic modalities for evaluation, diagnosis, and management of stroke, systemic and pulmonary embolism. This document provides comprehensive American Society of Echocardiography guidelines on the use of echocardiography for evaluation of cardiac sources of embolism. It describes general mechanisms of stroke and systemic embolism; the specific role of cardiac and aortic sources in stroke, and systemic and pulmonary embolism; the role of echocardiography in evaluation, diagnosis, and management of cardiac and aortic sources of emboli including the incremental value of contrast and 3D echocardiography; and a brief description of alternative imaging techniques and their role in the evaluation of cardiac sources of emboli. Specific guidelines are provided for each category of embolic sources including the left atrium and left atrial appendage, left ventricle, heart valves, cardiac tumors, and thoracic aorta. In addition, there are recommendation regarding pulmonary embolism, and embolism related to cardiovascular surgery and percutaneous procedures. The guidelines also include a dedicated section on cardiac sources of embolism in pediatric populations.

The spatial QRS-T angle outperforms the Italian and Seattle ECG-based criteria for detection of hypertrophic cardiomyopathy in pediatric patients.

INTRODUCTION: The spatial peaks QRS-T angle has been shown to differentiate adult patients with hypertrophic cardiomyopathy (HCM) from controls. We hypothesized that the spatial peaks QRS-T angle would, in isolation, be more accurate than the Italian 12-lead ECG Pre-participation Screening criteria or the Seattle criteria for detecting hypertrophic cardiomyopathy (HCM) in pediatric patients. METHODS: A retrospective study of pediatric patients with HCM compared to age and gender-matched control patients was undertaken. Significance, odds ratios, sensitivity and specificity of HCM detection of the visually derived spatial peaks QRS-T angle were compared to those of traditional 12-lead ECG criteria using: 1) Italy's National Pre-participation Screening Programme criteria; and 2) described criteria from Seattle. RESULTS: ECG results from 130 pediatric HCM patients (14.2±4.4years) were compared to 470 control patients (normal echocardiograms, mean age 13.4±4.6years). Mean±standard deviation (SD) values for spatial peaks QRS-T angles were 120.4±40.7 and 21.3±13.7 degrees for HCM and controls, respectively (P<0.001). A spatial peaks QRS-T angle cutoff value of >54.9 degrees yielded greater sensitivity and specificity (93.1% and 98.7%, respectively) for detecting HCM over ECG criteria from Italy (68.5% and 48.1%, respectively) or Seattle (64.6% and 78.9%, respectively) with odds ratios at 1039.70 (95% CI 363.03 to 2977.67), 2.01 (95% CI 1.33 to 3.04) and 6.84 (4.49-10.44), respectively. CONCLUSION: In our cohort, a visually derived spatial peaks QRS-T angle has increased sensitivity and specificity for detection of HCM in pediatric patients compared to currently utilized Italian or Seattle ECG criteria.

Echocardiographic estimation of right ventricular stroke work in children with pulmonary arterial hypertension: comparison with invasive measurements.

BACKGROUND: Right ventricular (RV) failure is a key determinant of mortality in children with pulmonary arterial hypertension (PAH). RV stroke work (RVSW) can be estimated as the product of RV systolic pressure and stroke volume. The authors have shown that RVSW predicts adverse outcomes in this population when derived from hemodynamic data; noninvasive assessment of RVSW may be advantageous but has not been assessed. There are few data validating noninvasive versus invasive measurements in children with PAH. The aim of this study was to compare echocardiographically derived RVSW with RVSW determined from hemodynamic data. METHODS: This was a retrospective study, including subjects with idiopathic PAH and minor or repaired congenital heart disease. Forty-nine subjects were included, in whom cardiac catheterization and echocardiography were performed within 1 month. Fourteen additional patients were included in a separate cohort, in whom catheterization and echocardiography were performed simultaneously. Catheterization-derived RVSW was calculated as RV systolic pressure × (cardiac output/heart rate). Echocardiographically derived RVSW was calculated as 4 × (peak tricuspid regurgitant jet velocity)(2) × (pulmonary valve area × velocity-time integral). Statistics included the intraclass correlation coefficient and Bland-Altman analysis. RESULTS: Echocardiographically derived RVSW was linearly correlated with invasively derived RVSW (r = 0.74, P < .0001, intraclass correlation coefficient = 0.76). Bland-Altman analysis showed adequate agreement. Echocardiographically derived RV work was related to indexed pulmonary vascular resistance (r = 0.43, P = .002), tricuspid annular plane systolic excursion (r = 0.41, P = .004), and RV wall thickness (r = 0.62, P < .0001). CONCLUSIONS: The authors demonstrate that RV work, a potential novel index of RV function, can be estimated noninvasively and is related to pulmonary hemodynamics and other indices of RV performance.

Strain and Strain Rate Measured on Echocardiogram 1-3 Weeks after Starting Treatment Is Worse in Acute Dilated Cardiomyopathy Pediatric Patients with Poor Outcomes at One Year.

BACKGROUND: Predicting later outcome around time of diagnosis of acute dilated cardiomyopathy (DCM) is difficult. We hypothesized that strain and strain rate on initial and follow-up echoes were worse in patients with acute DCM from all causes with poor one-year outcomes. METHODS: This was a retrospective study including all patients with DCM aged 0-18 years with left ventricle dilation, low ejection fraction, or low fractional shortening on initial echo. Longitudinal and circumferential strain and systolic and diastolic strain rate were measured on echo at presentation, 1-3 weeks after presentation, and at 1 year. Patients were separated into "Stable" (survivors) and "Progressive" (referred for transplant or died) outcome groups, and results were analyzed to determine whether strain or strain rate at each echo was worse in the "Stable" group compared with the "Progressive" group. RESULTS: The patient population included patients with DCM from idiopathic causes, myocarditis, iron deficiency anemia, lupus, chemotherapy, and LV noncompaction. Longitudinal and circumferential strain and systolic strain rate were significantly better in the "Stable" (n = 7) compared with the "Progressive" (n = 8) outcome group on 1- to 3-week echo. Longitudinal strain more negative than -10% had 87% specificity and 100% sensitivity for predicting "stable" outcome (AUC 0.98), while circumferential strain more negative than -8% had 60% specificity and 100% sensitivity (AUC 0.83). CONCLUSIONS: Longitudinal and circumferential strain and systolic strain rate measured 1-3 weeks after starting therapy are worse in acute dilated cardiomyopathy patients with poor one-year outcomes. Further studies with less heterogeneity and more study subjects are needed.

RV stroke work in children with pulmonary arterial hypertension: estimation based on invasive haemodynamic assessment and correlation with outcomes.

BACKGROUND: RV performance is an important determinant of outcomes in children with pulmonary arterial hypertension (PAH). RV stroke work (RVSW), the product of mean pulmonary artery pressure and stroke volume, integrates contractility, afterload and ventricular-vascular coupling. RVSW has not been evaluated in children with PAH. We tested the hypothesis that RVSW would be a predictor of outcomes in children with PAH. METHODS: Patients in the Children's Hospital Colorado PAH database were evaluated retrospectively, and those with idiopathic PAH and those with minor or repaired congenital heart disease were included. Haemodynamic data were obtained by catheterisation and echocardiography, performed within 3 months. RVSW was calculated: mean pulmonary arterial pressure × stroke volume, and indexed to body surface area. Statistics included Kruskal-Wallis, Wilcoxon rank sum, and Spearman correlation. RESULTS: Fifty patients were included. Median age of the cohort was 9.5 (6.0, 15.7) years, with a median indexed pulmonary vascular resistance (PVRi) of 6.5 (3.7, 11.6) WU m(2). RVSW had a significant association with PVRi (r=0.6, p<0.0001), tricuspid annular systolic plane excursion (r=0.55, p=0.0001), and RV fractional area change (r=-0.4, p=0.005). Grouped by WHO class, there was a significant difference in RVSW (p=0.04). Need for atrial septostomy and death were associated with higher RVSW (p=0.04 and p=0.03, respectively). CONCLUSIONS: RVSW can be estimated in children with PAH, and is significantly associated with abnormal WHO class, the need for septostomy, as well as mortality. Indices accounting for RV performance as well as ventricular-vascular coupling may be useful in the prognosis and, hence, management of children with PAH.

Left ventricular strain and strain rates are decreased in children with normal fractional shortening after exposure to anthracycline chemotherapy.

BACKGROUND: Anthracycline chemotherapeutic agents carry the well-recognised risk of cardiotoxicity. Previous methods to evaluate cardiac function are useful, but have significant limitations. We sought to determine the left ventricular strain and strain rate of paediatric cancer patients with normal fractional shortening treated with anthracyclines using the latest ultrasound feature-tracking technology. PATIENTS AND METHODS: Echocardiograms on cancer patients before anthracycline exposure and following completion of treatment were retrospectively analysed using Velocity Vector Imaging software in the circumferential and longitudinal planes. The same analysis was performed on matched controls. Only patients with a fractional shortening ≥28% were included. RESULTS: In all, 71 patients were identified with an age at diagnosis of 10.5 ± 4.7 years. The time from diagnosis to follow-up was 3.9 ± 4.0 years and the cumulative anthracycline dose was 356 ± 106 mg/m². Following anthracycline exposure, paediatric cancer patients had a higher heart rate and a lower longitudinal strain, longitudinal diastolic strain rate, circumferential strain, and circumferential systolic and diastolic strain rate when compared with controls. Diastolic strain rate showed the greatest percent difference following anthracycline exposure versus controls. CONCLUSION: Despite having a normal fractional shortening, children exposed to anthracyclines have subclinical derangement of their left ventricular deformation as measured by decreases in strain and strain rate in both the circumferential and longitudinal axis. In particular, there was a profound decrease in diastolic strain rate following anthracycline exposure compared with controls. Whether the decline of strain or strain rate can predict future risk of developing cardiomyopathy requires further investigation.

Longitudinal myocardial deformation is selectively decreased after pediatric cardiac transplantation: a comparison of children 1 year after transplantation with normal subjects using velocity vector imaging.

The transplanted heart experiences numerous hemodynamic changes during and after cardiac transplantation. This study sought to evaluate the left ventricular myocardial mechanics in the pediatric heart transplant population using Velocity Vector Imaging (VVI). This study retrospectively evaluated 28 heart transplant recipients by echocardiography 12 months after transplantation. Echocardiograms from 28 age- and gender-matched subjects were used as a control group. Peak global longitudinal and circumferential left ventricular strain, systolic strain rate, and diastolic strain rate were obtained. Student's t tests were used to assess differences between the two groups (defined as p ≤ 0.05). The peak global left ventricular longitudinal strain was lower in the transplant group (17.21%) than in the control group (22.14%). The transplant and control groups did not differ significantly in terms of their peak global circumferential strain (20.28% vs. 20.79%, respectively). Similar results were observed for longitudinal and circumferential systolic and diastolic strain rates. The transplant patients showed statistically significant reductions in all peak global longitudinal measures compared with those of the control subjects. Circumferential myocardial deformation appears to be preserved in transplant recipients. This could suggest evidence of ischemia given the known myocardial fiber arrangement of longitudinal fibers toward the endocardial surface, which is also more distal in the coronary arterioles.

Assessment of the relationship between Contegra conduit size and early valvar insufficiency.

BACKGROUND: Contegra bovine jugular vein (BJV) conduit results vary widely, and little attention has been directed at assessment of early conduit insufficiency. Conduit insufficiency is graded subjectively, and criteria vary. Several studies have used branch pulmonary artery flow reversal (BPAFR) to define severe conduit insufficiency. BJV valves are larger than human pulmonary valves of similar diameter. We hypothesize that anatomic differences between BJV and human pulmonary valves limit the use of BPAFR in the evaluation of BJV competence. Our purposes were to (1) assess the prevalence of early and 6-month BJV conduit insufficiency in our patients, (2) determine if conduit size affects BJV competence, and (3) determine if BPAFR is a specific discriminator of severe conduit insufficiency. METHODS: We reviewed 135 BJV conduits. One cardiologist blinded to original reports reviewed postoperative and 6-month echocardiograms. Conduits were grouped by size: group 1, 12 to 14 mm (n=51), and group 2, 16 to 22 mm (n=84). Moderate or greater insufficiency was considered clinically significant. RESULTS: Early conduit insufficiency was common in group 1 (37%) and rare in group 2 (5%, p<0.0001). After excluding conduits with significant insufficiency, BPAFR occurred in 18% (group 1, 27%; group 2, 13%; p=0.02). At follow-up, insufficiency worsened in group 1 but was stable in group 2. CONCLUSIONS: Early conduit insufficiency is common and worsens with follow-up in small BJVs. Conduit insufficiency is limited in larger sizes and remains stable. BJV exhibits BPAFR commonly in the absence of significant conduit insufficiency. BPAFR should not be used as a primary criterion for grading insufficiency in BJV conduits.