The current state and potential innovation of fetal cardiac MRI.

Fetal cardiac MRI is a rapidly evolving form of diagnostic testing with utility as a complementary imaging modality for the diagnosis of congenital heart disease and assessment of the fetal cardiovascular system. Previous technical limitations without cardiac gating for the fetal heart rate has been overcome with recent technology. There is potential utility of fetal electrocardiography for direct cardiac gating. In addition to anatomic assessment, innovative technology has allowed for assessment of blood flow, 3D datasets, and 4D flow, providing important insight into fetal cardiovascular physiology. Despite remaining technical barriers, with increased use of fCMR worldwide, it will become an important clinical tool to improve the prenatal care of fetuses with CHD.

Peak Oxygen Consumption (V̇O 2peak ) Recovery Delay in a Pediatric Fontan Population.

PURPOSE: The purpose of this study is to identify predictors and correlates of VO2RD in youth with Fontan. METHODS: Cardiopulmonary exercise test data was used from a single center, cross-sectional study of children and adolescents (age, 8-21 yr) with Fontan physiology. The VO2RD was determined using time (s) to <90% of V̇O 2peak and categorized as "low" (≤10 s) or "high" (≥10 s). t Tests and χ 2 analysis were used to compare continuous and categorical variables, respectively. RESULTS: The analysis sample included 30 adolescents with Fontan physiology (age, 14.2 ± 2.4 yr; 67% male) with either right ventricular (RV) dominant (40%) or co/left ventricular (Co/LV) dominant (60%) systemic ventricular morphology. There were no differences in V̇O 2peak between the high and low VO2RD groups (high = 1.3 ± 0.4 L·min -1 ; low = 1.3 ± 0.3 L·min -1 ; P = 0.97). VO2RD in participants with RV dominance was significantly greater than in patients with Co/LV dominance (RV = 23.8 ± 15.8 s; Co/LV = 11.8 ± 16.1 s; P = 0.03). CONCLUSIONS: V̇O 2peak was not correlated with VO2RD when analyzed as high/low VO2RD groups. However, morphology of the systemic single ventricle (RV vs Co/LV) may be related to rate of recovery in V̇O 2 after a peak cardiopulmonary exercise test.

Moderators of peak respiratory exchange ratio during exercise testing in children and adolescents with Fontan physiology.

OBJECTIVES: Many patients with Fontan physiology are unable to achieve the minimum criteria for peak effort during cardiopulmonary exercise testing. The purpose of this study is to determine the influence of physical activity and other clinical predictors related to achieving peak exercise criteria, signified by respiratory exchange ratio ≥ 1.1 in youth with Fontan physiology. METHODS: Secondary analysis of a cross-sectional study of 8-18-year-olds with single ventricle post-Fontan palliation who underwent cardiopulmonary exercise testing (James cycle protocol) and completed a past-year physical activity survey. Bivariate associations were assessed by Wilcoxon rank-sum test and simple regression. Conditional inference forest algorithm was used to classify participants achieving respiratory exchange ratio > 1.1 and to predict peak respiratory exchange ratio. RESULTS: Of the n = 43 participants, 65% were male, mean age was 14.0 ± 2.4 years, and 67.4% (n = 29) achieved respiratory exchange ratio ≥ 1.1. Despite some cardiopulmonary exercise stress test variables achieving statistical significance in bivariate associations with participants achieving respiratory exchange ratio > 1.1, the classification accuracy had area under the precision recall curve of 0.55. All variables together explained 21.4% of the variance in respiratory exchange ratio, with peak oxygen pulse being the most informative. CONCLUSION: Demographic, physical activity, and cardiopulmonary exercise test measures could not classify meeting peak exercise criteria (respiratory exchange ratio ≥ 1.1) at a satisfactory accuracy. Correlations between respiratory exchange ratio and oxygen pulse suggest the augmentation of stroke volume with exercise may affect the Fontan patient's ability to sustain high-intensity exercise.

Single ventricular strain measures correlate with peak oxygen consumption in children and adolescents with Fontan circulation.

INTRODUCTION: Children with a single ventricle post-Fontan palliation are at increased risk of poor outcomes with peak oxygen consumption acting as a surrogate outcome marker. The purpose of this study is to evaluate the relationship between peak oxygen consumption and echocardiographic measures of ventricular function and deformation, including ventricular global longitudinal strain and dyssynchrony, in children and adolescents following Fontan palliation. METHODS: Patients (age 8-21 years) with single ventricle post-Fontan palliation were prospectively recruited and participated in an echocardiogram, including views optimised for two-dimensional speckle tracking, and a cardiopulmonary exercise test on a cycle ergometer to maximal volitional fatigue. RESULTS: Thirty-eight patients (mean age 13.7 ± 2.3 years) post-Fontan palliation had either a single left ventricular (n = 20), single right ventricular (n = 14), or biventricular (n = 4) morphology. Peak oxygen consumption (24.9 ± 5.6 ml/kg/minute) was correlated with global longitudinal strain (r = -0.435, p = 0.007), a strain discoordination time to peak index (r = -0.48, p = 0.003), and the presence of an electro-mechanical dyssynchrony strain pattern (p = 0.008). On multivariate regression modelling, these three variables were associated with peak oxygen consumption independently of age and sex. The single right ventricular group had evidence of possible diastolic dysfunction by E/e' compared to the single left ventricular and biventricular groups (p = 0.001). CONCLUSIONS: Strain analysis measures are correlated with peak oxygen consumption in this cohort of children, adolescents, and young adults following Fontan palliation, suggesting that ventricular mechanics may influence the efficiency of the Fontan circulation.

"The Mental Health Piece is Huge": perspectives on developing a prenatal maternal psychological intervention for congenital heart disease.

OBJECTIVES: Women carrying a fetus diagnosed with congenital heart disease often experience significant distress because of their medical diagnosis. Given the well-documented impact associated with elevated prenatal stress and critical importance of developing targeted interventions, this study aims to examine stressors, coping and resilience resources, and mental health treatment preferences in pregnant women receiving a congenital heart disease diagnosis to inform the development of a psychological intervention to reduce maternal distress prenatally. METHODS: Three groups of participants were included consisting of two pregnant women carrying a fetus with congenital heart disease, five women of children (4-16 months) with congenital heart disease, and five paediatric cardiology medical providers. Responses were gathered via semi-structured interviews and analysed using qualitative thematic analysis. RESULTS: Information regarding four broad areas were analysed of emotional distress during pregnancy; experience of initial diagnosis; coping and resilience; and perspectives on a mental health intervention in pregnancy. Anxiety regarding baby's future, guilt following diagnosis, and various coping strategies emerged as primary themes among the participant sample. Medical staff corroborated mothers' heightened anxiety and viewed a psychotherapeutic intervention during the prenatal period as essential and complimentary to standard of care. CONCLUSION: We identified salient themes and preferred components for a future psychological intervention delivered prenatally. PRACTICE IMPLICATIONS: Patients' and providers' perspectives regarding the nature of maternal distress, resilience and treatment preferences can inform the development of interventions to support the emotional well-being of pregnant women carrying a fetus with congenital heart disease to optimise care and potentially improve outcomes for fetal brain development.

Ability of Video Telemetry to Predict Unplanned Hospital Admissions for Single Ventricle Infants.

Background Our Cardiac High Acuity Monitoring Program (CHAMP) uses home video telemetry (HVT) as an adjunct to monitor infants with single ventricle during the interstage period. This study describes the development of an objective early warning score using HVT, for identification of infants with single ventricle at risk for clinical deterioration and unplanned hospital admissions (UHA). Methods and Results Six candidate scoring parameters were selected to develop a pragmatic score for routine evaluation of HVT during the interstage period. We evaluated the individual and combined ability of these parameters to predict UHA. All infants with single ventricle monitored at home by CHAMP between March 2014 and March 2018 were included. Videos obtained within 48 hours before UHA were compared with videos obtained at baseline. We used binary logistic regression models and receiver operating characteristic curves to evaluate the parameters' performance in discriminating the outcome of interest. Thirty-nine subjects with 64 UHA were included. We compared 64 pre-admission videos to 64 paired baseline videos. Scoring was feasible for a mean of 91.6% (83.6%-98%) of all observations. Three different HVT score models were proposed, and a final model composed of respiratory rate, respiratory effort, color, and behavior exhibited an excellent discriminatory capability with an area under the receiver operating characteristic curve of 93% (89%-98%). HVT score of 5 was associated with specificity of 93.8% and sensitivity of 88.7% in predicting UHA. Conclusions We developed a feasible and reproducible HVT score that can serve as a tool to predict UHA in infants with single ventricle. Future directions involve prospective, multicenter validation of this tool.

Intervendor Agreement for Right Ventricular Global Longitudinal Strain in Children.

BACKGROUND: Right ventricular global longitudinal strain (RVGLS) has emerged as an important technique for clinical evaluation of (RV) function. The routine application of RVGLS in pediatrics remains limited by a lack of data on agreement between vendors. The aim of this study was to investigate intervendor agreement for RVGLS between the two commonly used analysis vendors in pediatrics, hypothesizing that RVGLS has good intervendor agreement, although it is likely lower than intravendor agreement (inter- and intraobserver reproducibility). METHODS: Seventy infants and children with normal cardiac anatomy and varying ventricular function were included after prospectively obtaining RV-focused four-chamber apical images on the GE Vivid E95. Images were analyzed for RVGLS at acquired frame rates in EchoPAC (GE) and TomTec (TT) and in the compressed Digital Imaging and Communications in Medicine format in TT. Intraclass correlation coefficients and Bland-Altman plots were used to test intervendor agreement and intravendor reproducibility. RESULTS: RVGLS measurements were equally feasible using TT and EchoPAC analysis (92%). There was good to excellent agreement for RVGLS between TT and EchoPAC analysis, with a relatively higher intraclass correlation coefficient between GE and TT at the acquired frame rate (0.85) than between GE and TT at the compressed frame rate (0.75) and significantly higher agreement in patients with abnormal RV function (0.7-0.9) than those with normal function (0.4-0.6). Intra- andinterobserver reproducibility for RVGLS was excellent (intraclass correlation coefficient = 0.74-0.96). Heart rate ≥ 100 beats/min and acquisition frame rate/heart rate ≤ 0.7 were associated with diminished agreement, especially when compressed data were involved. CONCLUSIONS: RVGLS analyzed using EchoPAC and TT show good agreement, especially when analyzed at acquisition frame rates and in the setting of abnormal RV function. Otherwise, RVGLS should ideally be analyzed using the same vendor, and intervendor comparisons should be undertaken with caution, particularly if data are in a compressed format.

Clinical pathway for the Fontan patient to standardise care and improve outcomes.

INTRODUCTION: The Fontan procedure is the final stage of surgical palliation for the children with functionally single ventricle anatomy. The post-operative medical management of this patient population can be variable and hospital length of stay prolonged. The purpose of this quality improvement project was to determine if the implementation of an evidence-based clinical pathway for post-operative management of the Fontan patient at a large Midwestern academic paediatric medical centre would standardise care and decrease length of stay. MATERIALS AND METHODS: The clinical pathway was developed using key components from three published pathways for the Fontan procedure from other paediatric institutions across the United States. Components of the clinical pathway included (1) supplemental oxygen until pleural drainage tubes are removed, (2) fluid restriction to 80% daily maintenance and a prescribed low-fat diet, (3) aggressive and standardised diuretic therapy while inpatient and (4) central venous access. The pathway was trialed using Plan-Do-Study-Act cycles in 2016, implemented in 2017 and sustained in 2018-2019. A retrospective electronic medical record review was performed to compare key outcomes from pre-pathway (2014-2015, 37 patients) with post-pathway implementation (2017-2018, 30 patients). RESULTS: Adherence to the pathway was nearly 100% with a statistically significant decrease in length of stay from 12 to 9 days (p = 0.007) and no increase in readmissions. CONCLUSION: Standardising care can improve clinical and financial outcomes for the Fontan patient population without negatively impacting quality of care, thus providing a positive benefit to the healthcare institution, industry and patient.

Translation of the Frailty Paradigm from Older Adults to Children with Cardiac Disease.

Children and adolescents with cardiac disease (CCD) have significant morbidity and lower quality of life. However, there are no broadly applicable tools similar to the frailty score as described in the elderly, to define functional phenotype in terms of physical capability and psychosocial wellbeing in CCD. The purpose of this study is to investigate the domains of the frailty in CCD. We prospectively recruited CCD (8-17.5 years old, 70% single ventricle, 27% heart failure, 12% pulmonary hypertension; NYHA classes I, II and III) and age and gender matched healthy controls (total n = 56; CCD n = 34, controls n = 22; age 12.6 ± 2.6 years; 39.3% female). We measured the five domains of frailty: slowness, weakness, exhaustion, body composition and physical activity using developmentally appropriate methods. Age and gender-based population norms were used to obtain Z scores and percentiles for each measurement. Two-tailed t-tests were used to compare the two groups. The CCD group performed significantly worse in all five domains of frailty compared to healthy controls. Slowness: 6-min walk test with Z score -3.9 ± 1.3 vs -1.4 ± 1.3, p < 0.001; weakness: handgrip strength percentile 18.9 ± 20.9 vs 57.9 ± 26.0, p < 0.001; exhaustion: multidimensional fatigue scale percentile 63.7 ± 13.5 vs 83.3 ± 14.4, p < 0.001; body composition: height percentile 43.4 ± 29.5 vs 71.4 ± 25.2, p < 0.001, weight percentile 46.0 ± 36.0 vs 70.9 ± 24.3, p = 0.006, BMI percentile 48.4 ± 35.5 vs 66.9 ± 24.2, p = 0.04, triceps skinfold thickness 41.0 ± 24.0 vs 54.4 ± 22.1, p = 0.04; physical activity: pediatric activity questionnaire score 2 ± 0.6 vs 2.7 ± 0.6, p < 0.001. The domains of frailty can be quantified in children using developmentally appropriate methods. CCD differ significantly from controls in all five domains, supporting the concept of quantifying the domains of frailty. Larger longitudinal studies are needed to study frailty in CCD and examine if it predicts adverse health outcomes.Clinical Trial Registration: The ClinicalTrials.gov identification number is NCT02999438. https://clinicaltrials.gov/ct2/show/NCT02999438.

Reproducibility and Intervendor Agreement of Left Ventricular Global Systolic Strain in Children Using a Layer-Specific Analysis.

BACKGROUND: Speckle-tracking strain analysis provides additive data to the assessment of pediatric and congenital heart disease; however, the variety of strain analysis software platforms by different vendors and the lack of data on intervendor strain agreement in children have limited its utility. The purpose of this study is to evaluate the intervendor agreement of strain on two commonly used analysis platforms in pediatrics by layer of myocardium and data compression. METHODS: This prospective study analyzed two-dimensional speckle-tracking strain on two software platforms in 53 children with normal cardiac segmental anatomy and varying function. Three standard apical views and one parasternal short-axis view were exported at their acquired frame rates to workstations with GE EchoPAC and TomTec software and then also to TomTec at compressed frame rates. Both software platforms had been updated with European Association of Cardiovascular Imaging/American Society of Echocardiography Task Force recommendations for left ventricular (LV) global strain. Intravendor and intervendor agreement between layer-specific comparisons were assessed using Bland-Altman analysis (limits of agreement and bias) and intraclass correlation coefficients. RESULTS: This study included subjects with normal LV function (n = 38) and cardiomyopathy (n = 15) with an age range of 1 month to 18 years. Intertechnique agreement by default vendor myocardial layer (GE mid-TomTec endocardial layer) was robust for both global longitudinal (GLS) and circumferential strain (GCS; higher for GLS than GCS). Intravendor (inter- and interreader) agreement was slightly higher than intervendor. Only small differences in intraclass correlation coefficients were present between various myocardial layers and acquired versus compressed TomTec data with narrow limits of agreement and small bias except in certain subgroup comparisons. CONCLUSIONS: Comparison of LV GLS and GCS between two commonly used software platforms after European Association of Cardiovascular Imaging/American Society of Echocardiography Industry Task Force recommendations demonstrated good to excellent agreement in pediatrics, regardless of the layer of analysis or the image format, although some degree of variability remains between vendor platforms. Overall, GLS agreement was more robust than GCS, and this difference is exaggerated in specific subanalyses. These data suggest that comparisons of strain values obtained on these two vendors will be reasonable, but caution should be used when the indication is the detection of small differences between serial echocardiograms.

Comparison of echocardiographic measurements to invasive measurements of diastolic function in infants with single ventricle physiology: a report from the Pediatric Heart Network Infant Single Ventricle Trial.

BACKGROUND: While echocardiographic parameters are used to quantify ventricular function in infants with single ventricle physiology, there are few data comparing these to invasive measurements. This study correlates echocardiographic measures of diastolic function with ventricular end-diastolic pressure in infants with single ventricle physiology prior to superior cavopulmonary anastomosis. METHODS: Data from 173 patients enrolled in the Pediatric Heart Network Infant Single Ventricle enalapril trial were analysed. Those with mixed ventricular types (n = 17) and one outlier (end-diastolic pressure = 32 mmHg) were excluded from the analysis, leaving a total sample size of 155 patients. Echocardiographic measurements were correlated to end-diastolic pressure using Spearman's test. RESULTS: Median age at echocardiogram was 4.6 (range 2.5-7.4) months. Median ventricular end-diastolic pressure was 7 (range 3-19) mmHg. Median time difference between the echocardiogram and catheterisation was 0 days (range -35 to 59 days). Examining the entire cohort of 155 patients, no echocardiographic diastolic function variable correlated with ventricular end-diastolic pressure. When the analysis was limited to the 86 patients who had similar sedation for both studies, the systolic:diastolic duration ratio had a significant but weak negative correlation with end-diastolic pressure (r = -0.3, p = 0.004). The remaining echocardiographic variables did not correlate with ventricular end-diastolic pressure. CONCLUSION: In this cohort of infants with single ventricle physiology prior to superior cavopulmonary anastomosis, most conventional echocardiographic measures of diastolic function did not correlate with ventricular end-diastolic pressure at cardiac catheterisation. These limitations should be factored into the interpretation of quantitative echo data in this patient population.

Medium-term assessment of cardiac function in pediatric cancer survivors. Comparison of different echocardiographic methods, cardiac MRI and cardiac biomarker testing in adolescent cancer survivors.

PURPOSE: To evaluate the feasibility and correlation of 3D echocardiography (echo) and cardiac biomarkers with cardiac MRI, in surveillance of cardiac function for cancer survivors. METHODS: Subjects ≥10 years of age who have survived >2 years after completion of cancer treatment from a single center were enrolled. Cardiac MRI and 3D echo images were obtained on the same day when routine echo was obtained. On the same day, along with annual routine blood test, cardiac biomarkers N-terminal pro-B-type natriuretic peptide levels (NT-proBNP) and troponin-I levels were also measured. RESULTS: Cardiac MRI was feasible in all 50 subjects. Three-dimensional echo and 2D echo images were of poor quality in four subjects. With a median duration of remission of 10 years, there were four subjects with mild LV dysfunction (cardiac MRI LV EF of<53%). None had MRI EF <50%, and nine subjects had LVEF <55%. M-mode echo overestimated EF more than 2D and 3D echo. Two-dimensional and 3D echo methods had much tighter limits of agreement for LV EF. For measurement of LVEF, 3D echo had a lower % error than 2D echo or M-mode echo. One subject had an abnormal troponin-I level and another one had an elevated NT-proBNP. CONCLUSIONS: Three-dimensional echo can be performed in most adolescent cancer survivors, and it correlates well with MRI. Further large-scale research is required in assessing utility of cardiac biomarkers in pediatric cancer survivors.

Speckle-Tracking Echocardiographic Measures of Right Ventricular Diastolic Function Correlate with Reference Standard Measures Before and After Preload Alteration in Children.

The accuracy of echocardiographic measures of right ventricular (RV) diastolic function has been sparsely studied. Our objective was to evaluate the correlation between echocardiographic and reference standard measures of RV diastolic function derived from micromanometer pressure analysis before and after preload alteration in children. Echocardiograms and micromanometer pressure analyses were prospectively performed before and after fluid bolus in children undergoing right heart catheterization. The isovolumic relaxation time constant (τ) and end-diastolic pressure (EDP) were measured. Conventional and speckle-tracking echocardiographic (STE) parameters of RV systolic and diastolic function were assessed. Normal saline bolus was given to increase RV EDP by 20 %. Twenty-eight studies were performed in 22 patients with congenital heart disease or postheart transplantation. Mean age was 8.7 ± 6.1 years. RV longitudinal early diastolic strain rate (EDSR) correlated with τ before (r = 0.57, p = 0.001) and after fluid bolus (r = 0.48, p = 0.008). No conventional echocardiographic measures correlated with τ both before and after fluid bolus. Multiple regression analysis revealed RV EDSR and LV circumferential EDSR as independent predictors of RV τ. There were no independent predictors of EDP. RV EDSR appears to correlate with the reference standard measure of early active ventricular relaxation in children at baseline and after changes in preload. Conventional echocardiographic measures of diastolic function were not predictive of diastolic function after preload alteration. Future studies should assess the prognostic significance of STE measures of diastolic function in this population.

Interpreting measurements of cardiac function using vendor-independent speckle tracking echocardiography in children: a prospective, blinded comparison with catheter-derived measurements.

BACKGROUND: Adult studies demonstrate that echocardiographic measurements of cardiac function using speckle tracking correlate with invasive measurements, but such data in the pediatric population are sparse. Our aim was to compare speckle-derived measures of cardiac function to measurements routinely obtained by cardiac catheterization in children. METHODS: Echocardiograms were performed on the day of cardiac catheterization. Using Tomtec 2D Cardiac Performance Analysis, longitudinal strain (LS), longitudinal strain rate (LSR), early diastolic LSR, and ejection fraction (EF) for the right and left ventricle (RV and LV) were calculated via speckle tracking. Global LS and LSR were calculated for the LV. These results were compared to cardiac index, maximum ventricular dp/dt (max dp/dt), ventricular end-diastolic pressure (EDP), and pulmonary capillary wedge pressure (PCWP) obtained by fluid-filled catheters. A blinded observer performed all echo measurements. RESULTS: Fifty studies were performed on 28 patients ages 4 months to 20 years old. Their diagnoses included cardiac transplant (48 studies), repaired AV septal defect (1), and dilated cardiomyopathy (1). RVEDP ranged from 2 to 22 mm Hg (median=6) and PCWP ranged from 6 to 32 mmHg (median 10). LV global LS and LV 2-chamber LSR by speckle-tracking negatively correlated with LV max dp/dt (LV global LS R=-.83, P=.001; LV 2-chamber LSR R=-.69, P=.009). RV LS weakly correlated with max dp/dt (R=.363, P=.002). Early diastolic strain rate did not correlate with EDP in either ventricle. CONCLUSION: Speckle-derived measurements of function in the LV have stronger correlation than the RV to catheter-derived measures. LV global LS has the strongest correlation with invasive function measures in children.

Echocardiography of coarctation of the aorta, aortic arch hypoplasia, and arch interruption: strategies for evaluation of the aortic arch.

Aim Echocardiography is the modality of choice for the diagnosis and serial follow-up of aortic arch pathology. In this article, we review the types of obstruction of the aortic arch, various classification schemes of coarctation of the aorta and interrupted aortic arch, methodology for optimal echocardiographic imaging of the aortic arch, and key echocardiographic measurements for accurate diagnosis of obstruction and hypoplasia of the aortic arch. Finally, we will discuss the limitations of echocardiography in optimal imaging of the aortic arch and the use of other non-invasive imaging modalities such as CT or MRI to provide additional information in these cases. BACKGROUND: Coarctation of the aorta is the more common lesion of the two, with an estimated incidence of four in every 10,000 live births in the United States of America. Interrupted aortic arch is rarer, with an incidence of 19 per one million live births. 1 There is a spectrum of pathology of obstruction of the aortic arch, ranging from coarctation of the aorta with and without hypoplasia of the arch to interrupted aortic arch. Both these lesions are frequently encountered in congenital cardiology practice, and will be discussed in the remainder of this article. Obstruction of the aortic arch in the setting of hypoplastic left heart structures or atresia of the aortic valve is beyond the scope of this review and will not be discussed further.