Cardiac atrial pathology in Duchenne muscular dystrophy.

INTRODUCTION/AIMS: Duchenne muscular dystrophy (DMD) is characterized by fibrofatty replacement of muscle. This has been documented in the ventricular myocardium of DMD patients, but there is limited description of atrial involvement. The purpose of this study is to examine the arrhythmia and ectopy burden in patients with DMD and non-DMD dilated cardiomyopathy (DCM) and to characterize the cardiac histopathologic changes in DMD patients across the disease spectrum. METHODS: This was a retrospective analysis of age-matched patients with DMD and non-DMD DCM who received a Holter monitor and cardiac imaging within 100 days of each other between 2010 and 2020. Twenty-four-hour Holter monitors were classified based on the most recent left ventricular ejection fraction at the time of monitoring. Cardiac histopathologic specimens from whole-heart examinations at the time of autopsy from three DMD patients and one DCM patient were reviewed. RESULTS: A total of 367 patients with 1299 Holter monitor recordings were included over the study period, with 94% representing DMD patients and 6% non-DMD DCM. Patients with DMD had more atrial ectopy across the cardiac function spectrum (p < 0.05). There was no difference in ventricular ectopy. Four DMD patients developed symptomatic atrial arrhythmias. Autopsy specimens from DMD patients demonstrated fibrofatty infiltration of both atrial and ventricular myocardium. DISCUSSION: The atrial myocardium in patients with DMD is unique. Autopsy specimens reveal fibofatty replacement of the atrial myocardium, which may be a nidus for both ectopy and arrhythmias in DMD patients.

Accelerated Cine Cardiac MRI Using Deep Learning-Based Reconstruction: A Systematic Evaluation.

BACKGROUND: Breath-holding (BH) for cine balanced steady state free precession (bSSFP) imaging is challenging for patients with impaired BH capacity. Deep learning-based reconstruction (DLR) of undersampled k-space promises to shorten BHs while preserving image quality and accuracy of ventricular assessment. PURPOSE: To perform a systematic evaluation of DLR of cine bSSFP images from undersampled k-space over a range of acceleration factors. STUDY TYPE: Retrospective. SUBJECTS: Fifteen pectus excavatum patients (mean age 16.8 ± 5.4 years, 20% female) with normal cardiac anatomy and function and 12-second BH capability. FIELD STRENGTH/SEQUENCE: 1.5-T, cine bSSFP. ASSESSMENT: Retrospective DLR was conducted by applying compressed sensitivity encoding (C-SENSE) acceleration to systematically undersample fully sampled k-space cine bSSFP acquisition data over an acceleration/undersampling factor (R) considering a range of 2 to 8. Quality imperceptibility (QI) measures, including structural similarity index measure, were calculated using images reconstructed from fully sampled k-space as a reference. Image quality, including contrast and edge definition, was evaluated for diagnostic adequacy by three readers with varying levels of experience in cardiac MRI (>4 years, >18 years, and 1 year). Automated DL-based biventricular segmentation was performed commercially available software by cardiac radiologists with more than 4 years of experience. STATISTICAL TESTS: Tukey box plots, linear mixed effects model, analysis of variance (ANOVA), weighted kappa, Kruskal-Wallis test, and Wilcoxon signed-rank test were employed as appropriate. A P-value <0.05 was considered statistically significant. RESULTS: There was a significant decrease in the QI values and edge definition scores as R increased. Diagnostically adequate image quality was observed up to R = 5. The effect of R on all biventricular volumetric indices was non-significant (P = 0.447). DATA CONCLUSION: The biventricular volumetric indices obtained from the reconstruction of fully sampled cine bSSFP acquisitions and DLR of the same k-space data undersampled by C-SENSE up to R = 5 may be comparable. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 1.

Extracardiac Findings on Cardiac Magnetic Resonance: A Children's Hospital Experience.

Cardiac magnetic resonance (CMR) incorporates a field of view that has the potential to capture clinically relevant extracardiac findings (ECF); however, there has been minimal investigation of ECF prevalence in children's hospitals, where the patient population varies in age and diagnosis. We retrospectively reviewed consecutive, clinically indicated, CMR studies performed at a tertiary care children's hospital during a 1-year period from January 1 to December 31, 2019. ECFs were classified as significant or non-significant based on whether they were described in the final impression of the CMR report. A total of 851 distinct patients had a CMR study during the 1-year period. Mean age was 19.5 (range 0.2; 74.2) years. A total of 254 ECFs were present in 158 of the 851 studies (18.6%) with 9.8% of all studies having significant ECFs. A total of 40.2% of ECFs were previously unknown and 9.1% (23/254) of ECFs included further recommendations (2.1% of all studies). ECFs were most often found in the chest (48%) or abdomen/pelvis (46%). Three patients were incidentally found to have malignancy (renal cell, thyroid, and hepatocellular carcinoma). Comparing studies with significant ECFs to the group without, CMR indications for biventricular CHD (43% vs 31%, p = 0.036), single ventricle CHD (12% vs 3.9%, p = 0.002), and aortopathy/vasculopathy (16% vs 7.6%, p = 0.020) were more common. The odds of significant ECF increased with increasing age (OR 1.82, 95% CI 1.10-3.01) and increased most notably between ages 14 to 33 years old. Recognition of the high percentage of ECFs remains important for timely diagnosis of these incidental findings.

Left Atrial Phasic Function via Cardiac Magnetic Resonance Imaging in Patients with Duchenne Muscular Dystrophy.

Cardiac dysfunction is a leading cause of morbidity and mortality in Duchenne muscular dystrophy (DMD). Left atrial (LA) function is a poorly understood concept in this patient population, and research suggests underlying structural changes that could affect atrial function. Cardiac magnetic resonance (CMR) imaging may provide an important non-invasive approach to evaluating LA function. This study was a single center retrospective review of consecutive CMR studies over a 1 year period comparing LA phasic function within a cohort of DMD patients, and to those with structurally and functionally normal hearts. LA strain measurements including global reservoir, conduit, boost-pump strain, and LA volumes were obtained retrospectively. Spearman correlation analyses were performed on atrial strain measurements. 107 DMD and 79 normal CMR studies were included. The DMD cohort had worse systolic function (p < 0.001), smaller indexed max LA and left ventricular (LV) volumes (p < 0.001), and greater LA emptying fraction (p < 0.001). In the DMD cohort, emptying fraction decreased with advanced patient age (p < 0.001) and diminishing systolic function (p < 0.001). DMD patients with moderate or severe LV dysfunction demonstrated lower LA emptying fraction (p = 0.002), more impaired 2-chamber LA reservoir (p = 0.003), and LA pump (p = 0.006) and conduit strain (p = 0.018). DMD patients with preserved function have lower indexed LA volumes with higher LA emptying fractions than controls. Progression of disease and age is associated with decreased LA emptying fraction with early manifestations in reservoir and conduit strain. These findings suggest that strain markers of LA compliance and early left ventricular relaxation are associated with worsening cardiomyopathy in the DMD population.

Cardiac Magnetic Resonance Imaging to Determine Single Ventricle Function in a Pediatric Population is Feasible in a Large Trial Setting: Experience from the Single Ventricle Reconstruction Trial Longitudinal Follow up.

The Single Ventricle Reconstruction (SVR) Trial was a randomized prospective trial designed to determine survival advantage of the modified Blalock-Taussig-Thomas shunt (BTTS) vs the right ventricle to pulmonary artery conduit (RVPAS) for patients with hypoplastic left heart syndrome. The primary aim of the long-term follow-up (SVRIII) was to determine the impact of shunt type on RV function. In this work, we describe the use of CMR in a large cohort follow up from the SVR Trial as a focused study of single ventricle function. The SVRIII protocol included short axis steady-state free precession imaging to assess single ventricle systolic function and flow quantification. There were 313 eligible SVRIII participants and 237 enrolled, ages ranging from 10 to 12.5 years. 177/237 (75%) participants underwent CMR. The most common reasons for not undergoing CMR exam were requirement for anesthesia (n = 14) or ICD/pacemaker (n = 11). A total of 168/177 (94%) CMR studies were diagnostic for RVEF. Median exam time was 54 [IQR 40-74] minutes, cine function exam time 20 [IQR 14-27] minutes, and flow quantification time 18 [IQR 12-25] minutes. There were 69/177 (39%) studies noted to have intra-thoracic artifacts, most common being susceptibility artifact from intra-thoracic metal. Not all artifacts resulted in non-diagnostic exams. These data describe the use and limitations of CMR for the assessment of cardiac function in a prospective trial setting in a grade-school-aged pediatric population with congenital heart disease. Many of the limitations are expected to decrease with the continued advancement of CMR technology.

Review of Cardiac Involvement in Multisystem Inflammatory Syndrome in Children.

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with substantial cardiovascular implications. Although infection with SARS-CoV-2 is usually mild in children, some children later develop a severe inflammatory disease that can have manifestations similar to toxic shock syndrome or Kawasaki disease. This syndrome has been defined by the US Centers for Disease Control and Prevention as multisystem inflammatory syndrome in children. Although the prevalence is unknown, >600 cases have been reported in the literature. Multisystem inflammatory syndrome in children appears to be more common in Black and Hispanic children in the United States. Multisystem inflammatory syndrome in children typically occurs a few weeks after acute infection and the putative etiology is a dysregulated inflammatory response to SARS-CoV-2 infection. Persistent fever and gastrointestinal symptoms are the most common symptoms. Cardiac manifestations are common, including ventricular dysfunction, coronary artery dilation and aneurysms, arrhythmia, and conduction abnormalities. Severe cases can present as vasodilatory or cardiogenic shock requiring fluid resuscitation, inotropic support, and in the most severe cases, mechanical ventilation and extracorporeal membrane oxygenation. Empirical treatments have aimed at reversing the inflammatory response using immunomodulatory medications. Intravenous immunoglobulin, steroids, and other immunomodulatory agents have been used frequently. Most patients recover within days to a couple of weeks and mortality is rare, although the medium- and long-term sequelae, particularly cardiovascular complications, are not yet known. This review describes the published data on multisystem inflammatory syndrome in children, focusing on cardiac complications, and provides clinical considerations for cardiac evaluation and follow-up.

Variation in Pharmacologic Management of Patients with Kawasaki Disease with Coronary Artery Aneurysms.

OBJECTIVE: To evaluate practice variation in pharmacologic management in the International Kawasaki Disease Registry (IKDR). STUDY DESIGN: Practice variation in intravenous immunoglobulin (IVIG) therapy, anti-inflammatory agents, statins, beta-blockers, antiplatelet therapy, and anticoagulation was described. RESULTS: We included 1627 patients from 30 IKDR centers with maximum coronary artery aneurysm (CAA) z scores 2.5-4.99 in 848, 5.0-9.99 in 349, and ≥10.0 (large/giant) in 430 patients. All centers reported IVIG and acetylsalicylic acid (ASA) as primary therapy and use of additional IVIG or steroids as needed. In 23 out of 30 centers, (77%) infliximab was also used; 11 of these 23 centers reported using it in <10% of their patients, and 3 centers used it in >20% of patients. Nonsteroidal anti-inflammatory agents were used in >10% of patients in only nine centers. Beta-blocker (8.8%, all patients) and abciximab (3.6%, all patients) were mainly prescribed in patients with large/giant CAAs. Statins (2.7%, all patients) were mostly used in one center and only in patients with large/giant CAAs. ASA was the primary antiplatelet modality for 99% of patients, used in all centers. Clopidogrel (18%, all patients) was used in 24 centers, 11 of which used it in >50% of their patients with large/giant CAAs. CONCLUSIONS: In the IKDR, IVIG and ASA therapy as primary therapy is universal with common use of a second dose of IVIG for persistent fever. There is practice variation among centers for adjunctive therapies and anticoagulation strategies, likely reflecting ongoing knowledge gaps. Randomized controlled trials nested in a high-quality collaborative registry may be an efficient strategy to reduce practice variation.

Myocarditis Cases Reported After mRNA-Based COVID-19 Vaccination in the US From December 2020 to August 2021.

Importance: Vaccination against COVID-19 provides clear public health benefits, but vaccination also carries potential risks. The risks and outcomes of myocarditis after COVID-19 vaccination are unclear. Objective: To describe reports of myocarditis and the reporting rates after mRNA-based COVID-19 vaccination in the US. Design, Setting, and Participants: Descriptive study of reports of myocarditis to the Vaccine Adverse Event Reporting System (VAERS) that occurred after mRNA-based COVID-19 vaccine administration between December 2020 and August 2021 in 192 405 448 individuals older than 12 years of age in the US; data were processed by VAERS as of September 30, 2021. Exposures: Vaccination with BNT162b2 (Pfizer-BioNTech) or mRNA-1273 (Moderna). Main Outcomes and Measures: Reports of myocarditis to VAERS were adjudicated and summarized for all age groups. Crude reporting rates were calculated across age and sex strata. Expected rates of myocarditis by age and sex were calculated using 2017-2019 claims data. For persons younger than 30 years of age, medical record reviews and clinician interviews were conducted to describe clinical presentation, diagnostic test results, treatment, and early outcomes. Results: Among 192 405 448 persons receiving a total of 354 100 845 mRNA-based COVID-19 vaccines during the study period, there were 1991 reports of myocarditis to VAERS and 1626 of these reports met the case definition of myocarditis. Of those with myocarditis, the median age was 21 years (IQR, 16-31 years) and the median time to symptom onset was 2 days (IQR, 1-3 days). Males comprised 82% of the myocarditis cases for whom sex was reported. The crude reporting rates for cases of myocarditis within 7 days after COVID-19 vaccination exceeded the expected rates of myocarditis across multiple age and sex strata. The rates of myocarditis were highest after the second vaccination dose in adolescent males aged 12 to 15 years (70.7 per million doses of the BNT162b2 vaccine), in adolescent males aged 16 to 17 years (105.9 per million doses of the BNT162b2 vaccine), and in young men aged 18 to 24 years (52.4 and 56.3 per million doses of the BNT162b2 vaccine and the mRNA-1273 vaccine, respectively). There were 826 cases of myocarditis among those younger than 30 years of age who had detailed clinical information available; of these cases, 792 of 809 (98%) had elevated troponin levels, 569 of 794 (72%) had abnormal electrocardiogram results, and 223 of 312 (72%) had abnormal cardiac magnetic resonance imaging results. Approximately 96% of persons (784/813) were hospitalized and 87% (577/661) of these had resolution of presenting symptoms by hospital discharge. The most common treatment was nonsteroidal anti-inflammatory drugs (589/676; 87%). Conclusions and Relevance: Based on passive surveillance reporting in the US, the risk of myocarditis after receiving mRNA-based COVID-19 vaccines was increased across multiple age and sex strata and was highest after the second vaccination dose in adolescent males and young men. This risk should be considered in the context of the benefits of COVID-19 vaccination.

Use of advanced cardiac imaging in congenital heart disease: growth, indications and innovations.

PURPOSE OF REVIEW: Significant improvements in the diagnosis and management of patients with congenital heart disease (CHD) have led to improved survival. These patients require life-long noninvasive evaluation. The use of advanced imaging such as cardiac magnetic resonance imaging (CMR) and cardiac computed tomography (CCT) has increased to support this need. The purpose of this review is to discuss the basics of advanced cardiac imaging, indications and review the recent innovations. RECENT FINDINGS: Recent literature has demonstrated the increasing reliance of advanced imaging for CHD patients. In addition, research is focusing on CMR techniques to shorten scan time and address previous limitations that made imaging younger and sicker patients more challenging. CCT research has involved demonstrating high-quality images with low radiation exposure. Advances in digital technology have impacted the interactivity of 3D imaging through the use of virtual and augmented reality platforms. With the increased reliance of advanced imaging, appropriate use criteria have been developed to address possible under or over utilization. SUMMARY: The utilization of advanced cardiac imaging continues to increase. As CMR and CCT continue to grow, increased knowledge of these modalities and their usage will be necessary for clinicians caring for CHD patients.

Cardiac Magnetic Resonance Imaging Evaluation of Neonatal Bronchopulmonary Dysplasia-associated Pulmonary Hypertension.

Rationale: Patients with bronchopulmonary dysplasia (BPD)-associated pulmonary hypertension (PH) have increased morbidity and mortality. Noninvasive assessment relies on echocardiograms (echos), which are technically challenging in this population. Improved assessment could augment decisions regarding PH therapies.Objectives: We hypothesized that neonatal cardiac magnetic resonance imaging (MRI) will correlate with BPD severity and predict short-term clinical outcomes, including need for PH therapies for infants with BPD.Methods: A total of 52 infants (31 severe BPD, 9 moderate BPD, and 12 with either mild or no BPD) were imaged between 39 and 47 weeks postmenstrual age on a neonatal-sized, neonatal ICU-sited 1.5-T magnetic resonance (MR) scanner. MR left ventricular eccentricity index (EI), main pulmonary artery-to-aorta (PA/AO) diameter ratio, and pulmonary arterial blood flow were determined. Echos obtained for clinical indications were reviewed. MRI and echo indices were compared with BPD severity and clinical outcomes, including length of stay (LOS), duration of respiratory support, respiratory support at discharge, and PH therapy.Measurements and Main Results: PA/AO ratio increased with BPD severity. Increased PA/AO ratio, MR-EI, and echo-EIs were associated with increased LOS and duration of respiratory support. No correlation was seen between pulmonary arterial blood flow and BPD outcomes. Controlling for gestational age, birth weight, and BPD severity, MR-EI was associated with LOS and duration of respiratory support. Increased PA/AO ratio and MR-EI were associated with PH therapy during hospitalization and at discharge.Conclusions: MRI can provide important image-based measures of cardiac morphology that relate to disease severity and clinical outcomes in neonates with BPD.

Left Atrial Strain in the Repaired Tetralogy of Fallot Population: Comparisons to Biventricular Function, Native T1 Values, Exercise Parameters and Healthy Controls.

BACKGROUND: Non-invasive imaging markers in patients with repaired tetralogy of Fallot (rTOF) are still being investigated to inform clinical decision making. Atrial function is a prognostic indicator in many acquired and congenital heart diseases. We sought to examine the relationship between cardiac MRI (CMR)-derived indices of left atrial (LA) function, native left ventricular (LV) T1 values, biventricular systolic function, and exercise capacity in rTOF. METHODS: Sixty-six patients with rTOF without prior pulmonary valve replacement who underwent CMR (median age 18.5 years) were identified. Twenty-one adult rTOF patients (age range 19-32 years) were compared with 20 age-matched healthy volunteers (age range 19-34 years). LA reservoir, conduit, and pump global longitudinal strain (GLS) and strain rate (SR) were determined by tissue tracking. Native LV T1 values were measured on rTOF patients. Pearson correlations were performed to determine bivariate associations. RESULTS: Adult rTOF patients had higher pump GLS, pump:conduit, and pump:reservoir GLS ratios, and lower conduit:reservoir GLS ratio, LV ejection fraction (EF), and right ventricular EF compared to controls (p < 0.001 for each comparison). LA conduit:reservoir GLS and pump:reservoir GLS had correlations to native LV T1 (ρ = 0.26, p = 0.03 and ρ = - 0.26, p = 0.03, respectively). LA reservoir SR had positive correlation to RV EF (ρ = 0.27, p = 0.03). There were no statistically significant correlations between LA function and exercise capacity. CONCLUSIONS: LA function is altered in adolescent and young adult patients with rTOF indicating worse diastolic function and relates to increasing native LV T1 values. Future studies are indicated to investigate the progression of adverse atrial-ventricular interactions and poor outcomes in this population.

Pediatric Myocardial T1 and T2 Value Associations with Age and Heart Rate at 1.5 T.

The objective of the study was to determine normal global left ventricular reference values for T1 and T2 in children. This is a retrospective study that included healthy subjects, age 5-19 years, who underwent CMR for the indication of pectus excavatum from 2018 to 2019. Linear regression models were used to determine associations of native T1 and T2 values to heart rate, age, and other CMR parameters. 102 patients with a mean age of 14.0 ± 2.4 years were included (range 5.4-18.8). 87 (85%) were males and 15 (15%) were females. The mean global T1 was 1018 ± 25 ms and the mean T2 was 53 ± 3 ms. T1 was negatively correlated with age (r = - 0.39, p < 0.001) and positively correlated with heart rate (r = 0.32, p < 0.001) by univariate analysis. Multivariable analysis showed that age and heart rate were independently associated with T1. T2 demonstrated a weak negative correlation with age (r = - 0.20, p = 0.047) and no correlation with heart rate. There was no difference in T1 (p = 0.23) or T2 (p = 0.52) between genders. This study reports normal pediatric T1 and T2 values at a 1.5 Tesla scanner. T1 was dependent on age and heart rate, while T2 was less dependent on age with no correlation with heart rate.

Rapid cardiac MRI protocol for cardiac assessment in paediatric and young adult patients undergoing haematopoietic stem cell transplant: a feasibility study.

BACKGROUND: Haematopoietic stem cell transplantation is an important and effective treatment strategy for many malignancies, marrow failure syndromes, and immunodeficiencies in children, adolescents, and young adults. Despite advances in supportive care, patients undergoing transplant are at increased risk to develop cardiovascular co-morbidities. METHODS: This study was performed as a feasibility study of a rapid cardiac MRI protocol to substitute for echocardiography in the assessment of left ventricular size and function, pericardial effusion, and right ventricular hypertension. RESULTS: A total of 13 patients were enrolled for the study (age 17.5 ± 7.7 years, 77% male, 77% white). Mean study time was 13.2 ± 5.6 minutes for MRI and 18.8 ± 5.7 minutes for echocardiogram (p = 0.064). Correlation between left ventricular ejection fraction by MRI and echocardiogram was good (ICC 0.76; 95% CI 0.47, 0.92). None of the patients had documented right ventricular hypertension. Patients were given a survey regarding their experiences, with the majority both perceiving that the echocardiogram took longer (7/13) and indicating they would prefer the MRI if given a choice (10/13). CONCLUSION: A rapid cardiac MRI protocol was shown feasible to substitute for echocardiogram in the assessment of key factors prior to or in follow-up after haematopoietic stem cell transplantation.

Cardiovascular magnetic resonance imaging derived septal curvature in neonates with bronchopulmonary dysplasia associated pulmonary hypertension.

BACKGROUND: Bronchopulmonary dysplasia (BPD) associated with pulmonary hypertension (PH) is a significant source of morbidity and mortality in premature infants. Recent advances have allowed the use of cardiovascular magnetic resonance (CMR) in the assessment of respiratory and cardiac disease in infants with BPD. In adults and older pediatric patients, decreased CMR interventricular septal curvature correlates with increased mean pulmonary artery pressure and pulmonary vascular resistance. The current study sought to determine the relationship of CMR derived septal curvature in neonates with BPD and BPD-PH with a need for PH therapy. METHODS: Forty moderate or severe BPD and 12 mild BPD or control infants were imaged without contrast between 38 and 47 weeks post-menstrual age on a neonatal-sized, neonatal intensive care unit-sited 1.5 T CMR scanner. CMR indices including eccentricity index (CMR-EI) and septal curvature were measured and compared to BPD severity and clinical outcomes including hospital length of stay (LOS), duration of respiratory support, respiratory support level at discharge and PH therapy. RESULTS: CMR-EI was directly associated and septal curvature was inversely associated with BPD severity. In a univariate analysis, CMR-EI and septal curvature were associated with increased hospital LOS, duration of respiratory support, respiratory support at hospital discharge, and need for PH therapy. In multivariable analysis CMR-EI was associated with hospital LOS and duration of respiratory support and septal curvature was associated with respiratory support at hospital discharge. Septal curvature was the only clinical or CMR variable associated with need for PH therapy (R2 = 0.66, p = 0.0014) in multivariable analysis demonstrating improved discrimination beyond CMR-EI. CONCLUSIONS: CMR derived septal curvature correlates significantly with clinical outcomes including hospital LOS, duration of respiratory support, respiratory support level at hospital discharge, and PH therapy in neonates with BPD and BPD-PH. Further, CMR derived septal curvature demonstrated improved discrimination of need for PH therapy and respiratory support at discharge compared to clinical variables and other CMR indices, supporting septal curvature as a non-invasive marker of PH in this population with potential to guide management strategies.

Physician variation in ordering of transthoracic echocardiography in outpatient pediatric cardiac clinics.

BACKGROUND: The pediatric Appropriate Use Criteria (AUC) for outpatient transthoracic echocardiography (TTE) aim to reduce practice variation. Little is known on variation in TTE use between physicians. Understanding this variation will help identify areas for improvement in standardization of TTE use. METHODS AND RESULTS: This is a retrospective review of initial outpatient visits at 6 pediatric cardiology centers in the United States prior to AUC release. Variation in TTE use was examined using multilevel generalized mixed effects models. Forward selection identified combinations of variables that explained the most variance in TTE use between physicians. Due to collinearity, physician compensation model and center were analyzed separately. Of 2883 encounters, the most common indication was murmur (36%), followed by chest pain (15.2%). Overall TTE use was 41.9%, and varied widely between centers (22.9%-52.6%), and between physicians within centers. Center alone explained 29% of this physician variance. Adding physician characteristics increased the variance explained to 57%, which only minimally improved by adding patient characteristics. The variance explained was driven by subspecialty. The center-based multivariable model explained more variance over compensation model. CONCLUSIONS: Center was the single largest determinant of physician variance in TTE use, followed by physician subspecialty. Efforts to reduce practice variation, such as the AUC, should be employed across centers and all pediatric cardiac providers. Center appears to have a stronger impact on variance than compensation model, though in this dataset the effect of center and compensation are hard to separate from each other and deserve further evaluation.

Echocardiographic versus angiographic measurement of the aortic valve annulus in children undergoing balloon aortic valvuloplasty: method affects outcomes.

OBJECTIVE: Operators are mindful of the balloon-to-aortic annulus ratio when performing balloon aortic valvuloplasty. The method of measurement of the aortic valve annulus has not been standardised. METHODS AND RESULTS: Patients who underwent aortic valvuloplasty at two paediatric centres between 2007 and 2014 were included. The valve annulus measured by echocardiography and angiography was used to calculate the balloon-to-aortic annulus ratio and measurements were compared. The primary endpoint was an increase in aortic insufficiency by ≥2 degrees. Ninety-eight patients with a median age at valvuloplasty of 2.1 months (Interquartile range (IQR): 0.2-105.5) were included. The angiographic-based annulus was 8.2 mm (IQR: 6.8-16.0), which was greater than echocardiogram-based annulus of 7.5 mm (IQR: 6.1-14.8) (p < 0.001). This corresponded to a significantly lower angiographic balloon-to-aortic annulus ratio of 0.9 (IQR: 0.9-1.0), compared to an echocardiographic ratio of 1.1 (IQR: 1.0-1.1) (p < 0.001). The degree of discrepancy in measured diameter increased with smaller valve diameters (p = 0.041) and in neonates (p = 0.044). There was significant disagreement between angiographic and echocardiographic balloon-to-aortic annulus ratio measures regarding "High" ratio of >1.2, with angiographic ratio flagging only 2/12 (16.7%) of patients flagged by echocardiographic ratio as "High" (p = 0.012). Patients who had an increase in the degree of aortic insufficiency post valvuloplasty, only 3 (5.5%) had angiographic ratio > 1.1, while 21 (38%) had echocardiographic ratio >1.1 (p < 0.001). Patients with resultant ≥ moderate insufficiency more often had an echocardiographic ratio of >1.1 than angiographic ratio of >1.1 There was no association between increase in balloon-to-aortic annulus ratio and gradient reduction. CONCLUSIONS: Angiographic measurement is associated with a greater measured aortic valve annulus and the development of aortic insufficiency. Operators should use caution when relying solely on angiographic measurement when performing balloon aortic valvuloplasty.

Comparison of inhospital outcomes of pediatric heart transplantation between single ventricle congenital heart disease and cardiomyopathy.

Data investigating the impact of household income and other factors on SV patient status-post-Fontan palliation after heart transplantation are lacking. We aim to evaluate factors affecting outcomes after OHT in this population. The PHIS database was interrogated for either SV or myocarditis/primary CM who were 4 years or older who underwent a single OHT. There were 1599 patients with a median age of 13.2 years (IQR: 9.3-16.1). Total hospital costs were significantly higher in the SV group ($408 000 vs $294 000, P < 0.0001), but as median household income increased, the risk of inhospital mortality, post-transplant LOS, and LOS-adjusted total hospital costs all decreased. The risk of inhospital mortality increased 6.5% per 1 year of age increase at the time of transplant. Patients in the SV group had significantly more diagnoses than those in the CM group (21 vs 15, P < 0.0001) and had longer total hospital LOSs as a result of longer post-transplant courses (25 days vs 15, P < 0.0001). Increased median household income and younger age are associated with decreased resource utilization and improved inhospital mortality in SV CHD patients who undergo OHT. In conclusion, earlier consideration of OHT in this population, coupled with improved selection criteria, may increase survival in this population.

Real-Time Transthoracic Vector Flow Imaging of the Heart in Pediatric Patients.

In children with congenital heart defects, Doppler ultrasound is the standard, bedside imaging modality. However, precise characterization of blood flow is challenging due to angle-dependent and one-dimensional velocity estimation. Contrast agent free Vector Flow Imaging is a new ultrasound technology that enables angle-independent visualization of the detailed flow field. Two piglets, one with normal cardiac anatomy and one with congenital heart disease comprised of valvular pulmonary stenosis, a dilated main pulmonary artery, and an incomplete atrioventricular canal defect, were imaged transthoracically and epicardially using a BK Ultrasound bk5000 with built-in vector flow imaging and a 5MHz linear probe. Subsequently, two children, one with normal cardiac anatomy and one with congenital heart disease comprised of aortic valve stenosis and coarctation of the aorta were imaged transthoracically. Transthoracic two-dimensional echocardiography and vector flow imaging were readily performed in both animals and were limited only by the geometry of the porcine thorax. In addition, transthoracic vector flow imaging was successfully performed in both children, and abnormal flow secondary to cardiac anomalies was visible. Adequate penetration was obtained to a depth of 6.5 cm. Our group has previously demonstrated for the first time that transthoracic vector flow imaging echocardiography is feasible and practicable in pediatric-sized patients, and this paper describes examples of these concepts and in-depth comparisons with traditional imaging modalities. This paper demonstrates that commercially available vector flow imaging technology can be utilized in pediatric cardiac applications as a bedside transthoracic imaging modality, providing advanced detail of blood flow patterns within the cardiac chambers, across valves, and in the great arteries.

Characteristics of Non-postoperative Pediatric Pericardial Effusion: A Multicenter Retrospective Cohort Study from the Pediatric Health Information System (PHIS).

Little is known about the causes and risks of non-postoperative pericardial effusion (PCE) in pediatric patients. We sought to assess the diagnoses most frequently associated with admissions for PCE, and to determine if certain conditions were associated with higher in-hospital mortality and rates of readmission. Nationally distributed data from 44 pediatric hospitals in the 2004-2015 Pediatric Health Information System database were used to identify patients with hospital admissions for International Classification of Disease, Ninth Revision (ICD-9) codes for PCE and/or cardiac tamponade. Children with congenital heart disease were excluded. ICD-9 codes for conditions associated with PCE were grouped into eight categories: neoplastic, renal, autoimmune/inflammatory, pneumonia, viral, bacterial, hypothyroidism, and idiopathic. Multivariable models were used to evaluate odds of in-hospital mortality and readmission within 30 and 90 days. There were 9902 patients who met inclusion criteria. Total in-hospital mortality was 8.2% (n = 813); of those without a neoplastic diagnosis, mortality was 6.5% (n = 493/7543). Idiopathic PCE accounted for the most admissions (36%), followed by neoplasms (24%), pneumonia (20%), and autoimmune/inflammatory disease (19%). In multivariable models, odds of death were highest for neoplasms (adjusted odds ratio 3.83, p < 0.001) and renal disease (adjusted odds ratio 2.86, p < 0.001). Children with a neoplasm, renal disease, and those undergoing pericardiocentesis had the highest rates of readmission at 30 and 90 days. Children admitted with non-postoperative PCE have multiple associated conditions. Neoplasm and renal disease in the setting of PCE are associated with the highest odds of in-hospital mortality among concomitant conditions; children with a neoplasm, renal disease, and those undergoing pericardiocentesis have the highest odds of readmission.

Short-Axis Diastolic Ventricular Area Ratio as a New Index in Screening Patients with Repaired Tetralogy of Fallot.

Right ventricular (RV) end-diastolic volume measured by cardiovascular magnetic resonance imaging (CMR) is a criterion for pulmonary valve replacement in patients with tetralogy of Fallot (TOF). We sought to determine if the ratio of echocardiographic, short-axis RV-to-left ventricular (LV) end-diastolic areas (EDA) could be used to predict RV volume on CMR. We retrospectively reviewed the echocardiograms of all patients with repaired TOF who underwent CMR at our institution from 2011 to 2015 and also had an echocardiogram within 6 months of the CMR. The short-axis RV and LV EDAs were measured and the ratio of the two was calculated. Results were compared with CMR RV end-diastolic volume index (RVEDVi) and RV:LV end-diastolic volume ratio. The sensitivity and specificity values predicting RV volumes > 150 ml/m2 were calculated. Fifty-eight studies met inclusion criteria. There were 47 studies with RVEDVi < 150 ml/m2 and 11 with RVEDVi > 150 ml/m2. RV:LV EDA and CMR RV:LV end-diastolic volume ratio correlated strongly (r = 0.76, p < 0.0001). An RV:LV EDA ≥ 1.57 had a 90% sensitivity to predict RVEDVi > 150 ml/m2 (area under the curve = 0.74, 95% CI 1.5-27.9; p = 0.012). An RV:LV EDA ≥ 1.88 had an 81% specificity to detect RV volume index > 150 ml/m2. Short-axis RV:LV EDA correlates well with an increased RVEDVi as measured by CMR. This new and simple measure can be used to predict optimal timing for CMR in anticipation of pulmonary valve replacement in repaired TOF.