Practice Patterns of Cardiovascular Magnetic Resonance Use in the Diagnosis of Pediatric Myocarditis: A Survey-Based Study.

BACKGROUND: Cardiovascular magnetic resonance (CMR) is used to diagnose myocarditis in adults and children based on the original Lake Louise Criteria (LLC) and more recently the revised LLC. The major change included in the revised LLC was the incorporation of parametric mapping, which significantly increases the sensitivity and specificity of diagnosis. Subsequently, scientific statements have recommended the use of parametric mapping in the diagnosis of myocarditis in children. However, there are some challenges to parametric mapping that are unique to the pediatric population. Our goal is to characterize clinical CMR and parametric mapping practice patterns for diagnosis of myocarditis in pediatric centers. METHODS: The Cardiovascular Magnetic Resonance Evaluation in Return to Athletes for Myocarditis in COVID-19 and Immunization Consortium created a REDCap survey to evaluate clinical practice patterns for diagnosis of myocarditis in pediatrics. This survey was distributed to the Society for Cardiovascular Magnetic Resonance community. RESULTS: 59 responses from 51 centers were received, with only one response from each center being utilized. Only 35% of centers (37% of North America, 31% of international) reported using CMR routinely in all patients with a suspicion for myocarditis. Diagnostic uncertainty was noted as the most important reason for CMR, while cost was noted as the least important consideration. The majority of centers reported using the revised LLC (37/51, 72%) compared to original LLC (7/51, 14%) or a hybrid criteria (6/51, 12%). When looking at the use of parametric mapping, only 5/47 (11%) for T1 mapping and 11/49 (22%) for T2 mapping reported having scanner-specific pediatric normative data. CONCLUSION: Routine CMR imaging for diagnosis of myocarditis in pediatrics is infrequently performed at surveyed centers despite the focus on a group of non-invasive cardiac imagers. While the majority reported using parametric mapping, few centers reporting having pediatric scanner-specific normative data. This highlights an important gap in the utilization of CMR that may aid in the diagnosis of myocardial disease.

Design and implementation of multicenter pediatric and congenital studies with cardiovascular magnetic resonance: Big data in smaller bodies.

Cardiovascular magnetic resonance (CMR) has become the reference standard for quantitative and qualitative assessment of ventricular function, blood flow, and myocardial tissue characterization. There is a preponderance of large CMR studies and registries in adults; However, similarly powered studies are lacking for the pediatric and congenital heart disease (PCHD) population. To date, most CMR studies in children are limited to small single or multicenter studies, thereby limiting the conclusions that can be drawn. Within the PCHD CMR community, a collaborative effort has been successfully employed to recognize knowledge gaps with the aim to embolden the development and initiation of high-quality, large-scale multicenter research. In this publication, we highlight the underlying challenges and provide a practical guide toward the development of larger, multicenter initiatives focusing on PCHD populations, which can serve as a model for future multicenter efforts.

Assessment of Biventricular Systolic and Diastolic Function Using Conventional and Strain Echocardiography in Children with Sickle Cell Disease Surviving 1-year After Hematopoietic Stem Cell Transplant.

Hematopoietic stem cell transplant (HSCT) is a potentially curative therapy for children with sickle cell disease (SCD). The effects of HSCT on ventricular function are not well characterized in children with SCD. Echocardiograms from children with SCD who underwent HSCT between 2007 and 2017 were retrospectively analyzed before and 1-year after HSCT. Left ventricular (LV) volumes, mass, and ejection fraction were calculated by the 5/6 area*length method. LV end-diastolic and systolic dimensions, septal, and posterior wall thickness, and fractional shortening were measured by M-mode. Mitral and tricuspid inflow Dopplers (E and A waves) as well as mitral, tricuspid, and septal tissue Dopplers (E', A') were assessed. E/A, E'/A' and E/E' ratios were calculated. Biventricular strain imaging was performed using speckle-tracking echocardiography. Peak global systolic longitudinal and circumferential LV strain, and global longitudinal right ventricular strain, as well as early and late diastolic strain rate, were measured on LV apical 4-chamber, LV short-axis mid-papillary, and RV apical views, respectively. Forty-seven children (9.7 ± 5.5 years, 60% male) met inclusion criteria. Pre-HSCT, subjects had mild LV dilation with normal LV systolic function by conventional measure of ejection fraction and fractional shortening. There was a significant reduction in LV volume, mass, and ejection fraction after HSCT, but measurements remained within normal range. LV longitudinal and circumferential strain were normal pre-HSCT and showed no significant change post-HSCT. RV strain decreased after HSCT, but the absolute change was small, and mean values were normal both pre- and post-HSCT. Conventional measures of diastolic function were all normal pre-HSCT. Post-HSCT there was a reduction in select parameters, but all parameters remained within normal range. Early and late diastolic strain rate parameters showed no significant change from pre- to post-HSCT. At one-year after HSCT in children with SCD conventional measures of systolic and diastolic function are within normal limits. Except for a small decrease in RV systolic strain with values remaining within normal limits, systolic strain and diastolic strain rate values did not significantly change 1-year after HSCT.

Association Between High Sensitivity Troponin Levels Following Pediatric Orthotopic Heart Transplantation and Intensive Care Unit Resource Utilization.

The utility of troponin levels, including high sensitivity troponin T (hs-TnT), after orthotopic heart transplant (OHT) is controversial. Conflicting data exist regarding its use as a marker of acute rejection. Few studies have examined possible associations of hs-TnT levels immediately after OHT with metrics of intensive care unit (ICU) resource utilization or risk of acute rejection. We performed a retrospective cohort chart review including all OHT recipients < 20 years of age at our center between June 2019 and December 2022. Patients were divided into two groups based on supra- or sub-median initial hs-TnT levels (median 3462.5 ng/L). Primary outcome was days requiring ICU-level care, secondary outcomes included days intubated, days requiring positive pressure ventilation (PPV), days on inotropic medications, actual ICU length of stay, Vasoactive Inotrope Scores (VIS) on postoperative days (POD) 0 through 7, and acute rejection at 30 days and one year after OHT. Patients with higher hs-TnT required ICU level care for longer [13.5 (10-17.5) vs. 9.5 (8-12) days, p = 0.01] and spent more days intubated [6 (4-7) vs. 3 (3-5) days, p < 0.001], on PPV [9 (6-15) vs. 6 (5-8.5) days, p = 0.02], and on inotropes [11 (9-14) vs. 8 (7-11) days, p = 0.025]. VIS was only different between groups on POD7 [5 (3-7) vs. 3 (0-5), p = 0.04]. There was no difference in rejection between the groups. Higher hs-TnT immediately following pediatric OHT may predict higher ICU resource utilization, despite no difference in VIS, although it does not predict acute rejection in the first year after OHT.

Limited Relationship Between Echocardiographic Measures and Electrocardiographic Markers of Left Ventricular Size in Healthy Children.

Pediatric ECG standards have been defined without echocardiographic confirmation of normal anatomy. The Pediatric Heart Network Normal Echocardiogram Z-score Project provides a racially diverse group of healthy children with normal echocardiograms. We hypothesized that ECG and echocardiographic measures of left ventricular (LV) dimensions are sufficiently correlated in healthy children to imply a clinically meaningful relationship. This was a secondary analysis of a previously described cohort including 2170 digital ECGs. The relationship between 6 ECG measures associated with LV size were analyzed with LV Mass (LVMass-z) and left ventricular end-diastolic volume (LVEDV-z) along with 11 additional parameters. Pearson or Spearman correlations were calculated for the 78 ECG-echocardiographic pairs with regression analyses assessing the variance in ECG measures explained by variation in LV dimensions and demographic variables. ECG/echocardiographic measurement correlations were significant and concordant in 41/78 (53%), though many were significant and discordant (13/78). Of the 6 ECG parameters, 5 correlated in the clinically predicted direction for LV Mass-z and LVEDV-z. Even when statistically significant, correlations were weak (0.05-0.24). R2 was higher for demographic variables than for echocardiographic measures or body surface area in all pairs, but remained weak (R2 ≤ 0.17). In a large cohort of healthy children, there was a positive association between echocardiographic measures of LV size and ECG measures of LVH. These correlations were weak and dependent on factors other than echocardiographic or patient derived variables. Thus, our data support deemphasizing the use of solitary, traditional measurement-based ECG markers traditionally thought to be characteristic of LVH as standalone indications for further cardiac evaluation of LVH in children and adolescents.

Ventricular function and tissue characterization by cardiac magnetic resonance imaging following hospitalization for multisystem inflammatory syndrome in children: a prospective study.

BACKGROUND: Multisystem inflammatory syndrome in children (MIS-C) is a severe life-threatening manifestation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that often presents with acute cardiac dysfunction and cardiogenic shock. While recovery from acute illness is excellent, the long-term myocardial impact is unknown. OBJECTIVE: To compare cardiac MRI findings in children 6-9 months after their hospitalization with MIS-C against MRI findings in healthy controls to assess for residual myocardial disease. MATERIALS AND METHODS: We prospectively performed cardiac MRI on 13 children 6-9 months following their hospitalization with MIS-C: eight of these children had a history of left ventricle ejection fraction (LVEF) < 50%, persistent symptoms, or electrocardiogram (ECG) abnormalities and underwent clinical MRI; five of these children without cardiac abnormalities during their hospitalization underwent research MRIs. We compared their native T1 and T2 mapping values with those of 20 normal controls. RESULTS: Cardiac MRI was performed at 13.6 years of age (interquartile range [IQR] 11.9-16.4 years) and 8.2 months (IQR 6.8-9.6 months) following hospitalization. Twelve children displayed normal ejection fraction: left ventricle (LV) 57.2%, IQR 56.1-58.4; right ventricle (RV) 53.1%, IQR 52.0-55.7. One had low-normal LVEF (52%). They had normal extracellular volume (ECV) and normal T2 and native T1 times compared to controls. There was no qualitative evidence of edema. One child had late gadolinium enhancement (LGE) with normal ejection fraction, no edema, and normal T1 and T2 times. When stratifying children who had MIS-C according to history of LVEF <55% on echocardiography, there was no difference in MRI values. CONCLUSION: Although many children with MIS-C present acutely with cardiac dysfunction, residual myocardial damage 6-9 months afterward appears minimal. Long-term implications warrant further study.

Outcomes and Risk Factors of Interventions for Pediatric Post-operative Pulmonary Vein Stenosis.

Pulmonary vein stenosis (PVS) in children is a challenging condition with poor outcomes. Post-operative stenosis can occur after repair of anomalous pulmonary venous return (APVR) or stenosis within native veins. There is limited data on the outcomes of post-operative PVS. Our objective was to review our experience and assess surgical and transcatheter outcomes. Single-center retrospective study was performed including patients < 18 years who developed restenosis after baseline pulmonary vein surgery that required additional intervention(s) from 1/2005 to 1/2020. Non-invasive imaging, catheterization and surgical data were reviewed. We identified 46 patients with post-operative PVS with 11 (23.9%) patient deaths. Median age at index procedure was 7.2 months (range 1 month-10 years), and median follow-up was 10.8 months (range 1 day-13 years). Index procedure was surgical in 36 (78.3%) and transcatheter in 10 (21.7%). Twenty-three (50%) patients developed vein atresia. Mortality was not associated with number of affected veins, vein atresia, or procedure type. Single ventricle physiology, complex congenital heart disease (CCHD), and genetic disorders were associated with mortality. Survival rate was higher in APVR patients (p = 0.03). Patients with three or more interventions had a higher survival rate compared to patients with 1-2 interventions (p = 0.02). Male gender, necrotizing enterocolitis, and diffuse hypoplasia were associated with vein atresia. In post-operative PVS, mortality is associated with CCHD, single ventricle physiology, and genetic disorders. Vein atresia is associated with male gender, necrotizing enterocolitis, and diffuse hypoplasia. Multiple repeated interventions may offer a patient survival benefit; however, larger prospective studies are necessary to elucidate this relationship further.

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.

Left Ventricular Strain Normalizes After Balloon Aortic Valvuloplasty in Infants with Congenital Aortic Stenosis.

Severe aortic stenosis (AS) causes left ventricular (LV) afterload and subendocardial ischemia. Despite this, most infants with AS have normal LV ejection fraction (EF). Strain analysis using two-dimensional speckle tracking echocardiography (2DSTE) may identify more sensitive markers of systolic dysfunction. We sought to show changes in LV strain after balloon aortic valvuloplasty (BAV) in infants with AS. Twenty-seven infants ≤ 1 year of age with AS who underwent BAV from 2007 to 2017 were included. Echocardiograms before/after BAV were retrospectively analyzed with 2DSTE. Median age was 29 days (interquartile range 3-52) and LV EF was 64 ± 10%. Global longitudinal strain (GLS) significantly improved post-BAV (- 17 ± 5 vs. - 20 ± 4%, p = 0.001) with no difference in global circumferential strain. Peak longitudinal strain was abnormal at the inferoseptal base and mid-ventricle (- 15 ± 6 and - 17 ± 5 = 7%, respectively) and significantly improved in the basal and mid-anterolateral segments (- 17 ± 5 vs. - 21 ± 5%, p < 0.01; - 17 ± 6% vs. - 20 ± 5%, p = 0.01, respectively). Five (20%) patients underwent reintervention, and had significantly higher peak-to-peak pre and post-BAV AS gradients (86 ± 14 vs. 61 ± 20 mmHg, p = 0.02; 33 ± 17 vs. 21 ± 10 mmHg, p = 0.04, respectively). In conclusion, longitudinal strain is abnormal in infants with AS and improves to previously published normal values after BAV.

Impact of Obesity on Left Ventricular Thickness in Children with Hypertrophic Cardiomyopathy.

Obesity is associated with additional left ventricular hypertrophy (LVH) in adults with hypertrophic cardiomyopathy (HCM). It is not known whether obesity can lead to further LVH in children with HCM. Echocardiographic LV dimensions were determined in 504 children with HCM. Measurements of interventricular septal thickness (IVST) and posterior wall thickness (PWT), and patients' weight and height were recorded. Obesity was defined as a body mass index (BMI) ≥ 99th percentile for age and sex. IVST data was available for 498 and PWT data for 484 patients. Patient age ranged from 2 to 20 years (mean ± SD, 12.5 ± 3.9) and 340 (68%) were males. Overall, patient BMI ranged from 7 to 50 (22.7 ± 6.1). Obesity (BMI 18-50, mean 29.1) was present in 140 children aged 2-19.6 (11.3 ± 4.1). The overall mean IVST was 20.5 ± 9.6 mm and the overall mean PWT was 11.0 ± 8.4 mm. The mean IVST in the obese patients was 21.6 ± 10.0 mm and mean PWT was 13.3 ± 14.7 mm. The mean IVST in the non-obese patients was 20.1 ± 9.5 mm and mean PWT was 10.4 ± 4.3 mm. Obesity was not significantly associated with IVST (p = 0.12), but was associated with increased PWT (0.0011). Obesity is associated with increased PWT but not IVST in children with HCM. Whether obesity and its impact on LVH influences clinical outcomes in children with HCM needs to be studied.

Diastolic dysfunction in tetralogy of Fallot: Comparison of echocardiography with catheterization.

BACKGROUND: Right ventricular (RV) systolic dysfunction has been associated with adverse outcomes in tetralogy of Fallot (TOF). However, the role and etiology of diastolic dysfunction remain incompletely defined. We assessed the association between traditional echocardiographic measures of diastolic function with catheter-based RV end-diastolic pressure (RVEDP) and identified clinical characteristics independently associated with diastolic dysfunction. METHODS: Single-center, retrospective cohort study of surgically repaired TOF patients undergoing cardiac catheterization with echocardiograms within 3 months prior to the catheterization. Tricuspid inflow and tissue Doppler measurements (E/A, E/e', and deceleration time) defined diastolic dysfunction, graded as impaired relaxation, pseudonormal, or restrictive physiology. Regression analyses tested associations between echocardiographic parameters, RVEDP, and clinical characteristics. RESULTS: Ninety-four subjects were included. Catheterization age was 8.9 years (interquartile range 4.4, 15.9). RVEDP was 9.5 ± 2.5 mm Hg. Sixty-one (65%) subjects had echocardiographic evidence of diastolic dysfunction. RVEDP was not associated with echocardiographic parameters of diastolic function (grade of dysfunction, E/e', or E/A). Higher RVEDP was associated with larger right atrial and RV end-diastolic area, independently of weight and degree of pulmonary or tricuspid regurgitation, though was not associated with indexed right atrial or RV end-diastolic area. Greater number of interim procedures was associated with higher RVEDP, E/e', and the presence of diastolic dysfunction by echocardiography. CONCLUSIONS: Diastolic dysfunction, as determined by echocardiography-derived and catheter-based (RVEDP) measures, is prevalent in this TOF population. These measures are not associated with each other; therefore, echocardiographic parameters of diastolic function are not reflective of RVEDP. The development of noninvasive parameters that correlate with filling pressures is required.

Early postoperative remodelling following repair of tetralogy of Fallot utilising unsedated cardiac magnetic resonance: a pilot study.

IntroductionThe right ventricular adaptations early after surgery in infants with tetralogy of Fallot are important to understand the changes that occur later on in life; this physiology has not been fully delineated. We sought to assess early postoperative right ventricular remodelling in patients with tetralogy of Fallot by cardiac MRI.Materials and methodSubjects with tetralogy of Fallot under 1 year of age were recruited following complete surgical repair for tetralogy of Fallot. Protocol-based cardiac MRI to assess anatomy, function, and flows was performed before hospital discharge using the feed and sleep technique, an unsedated imaging technique. RESULTS: MRI was completed in 16 subjects at a median age of 77 days (interquartile range 114). There was normal ventricular ejection fraction and indexed right ventricular end-diastolic volume (48±13 cc/m2), but elevated right ventricular mass (z score 6.2±2.4). Subjects requiring a transannular patch or right ventricle to pulmonary artery conduit had moderate pulmonary insufficiency (regurgitant fraction 27±16%).DiscussionEarly right ventricular remodelling after surgical repair for tetralogy of Fallot is characterised by significant pulmonary regurgitation, right ventricular hypertrophy, and lack of dilation. Performing cardiac MRI using the feed and sleep technique is feasible in infants younger than 5 months. These results might open new avenues to study longitudinal right ventricular changes in tetralogy of Fallot and to further explore the utility of unsedated MRI in patients with other types of CHDs.

How best to assess right ventricular function by echocardiography.

Right ventricular function is a crucial determinant of long-term outcomes of children with heart disease. Quantification of right ventricular systolic and diastolic performance by echocardiography is of paramount importance, given the prevalence of children with heart disease, particularly those with involvement of the right heart, such as single or systemic right ventricles, tetralogy of Fallot, and pulmonary arterial hypertension. Identification of poor right ventricular performance can provide an opportunity to intervene. In this review, we will go through the different systolic and diastolic indices, as well as their application in practice. Quantification of right ventricular function is possible and should be routinely performed using a combination of different measures, taking into account each disease state. Quantification is extremely useful for individual patient follow-up. Laboratories should continue to strive to optimise reproducibility through quality improvement and quality assurance efforts in addition to investing in technology and training for new, promising techniques, such as three-dimensional echocardiography.

Valved Sano conduit improves immediate outcomes following Norwood operation compared with nonvalved Sano conduit.

OBJECTIVE: Use of a valved Sano during the Norwood procedure has been reported previously, but its impact on clinical outcomes needs to be further elucidated. We assessed the impact of the valved Sano compared with the nonvalved Sano after the Norwood procedure in patients with hypoplastic left heart syndrome. METHODS: We retrospectively reviewed 25 consecutive neonates with hypoplastic left heart syndrome who underwent a Norwood procedure with a valved Sano conduit using a femoral venous homograft and 25 consecutive neonates with hypoplastic left heart syndrome who underwent a Norwood procedure with a nonvalved Sano conduit between 2013 and 2022. Primary outcomes were end-organ function postoperatively and ventricular function over time. Secondary outcomes were cardiac events, all-cause mortality, and Sano and pulmonary artery reinterventions at discharge, interstage, and pre-Glenn time points. RESULTS: Postoperatively, the valved Sano group had significantly lower peak and postoperative day 1 lactate levels (P = .033 and P = .025, respectively), shorter time to diuresis (P = .043), and shorter time to enteral feeds (P = .038). The valved Sano group had significantly fewer pulmonary artery reinterventions until the Glenn operation (n = 1 vs 8; P = .044). The valved Sano group showed significant improvement in ventricular function from the immediate postoperative period to discharge (P < .001). From preoperative to pre-Glenn time points, analysis of ventricular function showed sustained ventricular function within the valved Sano group, but a significant reduction of ventricular function in the nonvalved Sano group (P = .003). Pre-Glenn echocardiograms showed competent conduit valves in two-thirds of the valved Sano group (n = 16; 67%). CONCLUSIONS: The valved Sano is associated with improved multi-organ recovery postoperatively, better ventricular function recovery, and fewer pulmonary artery reinterventions until the Glenn procedure.

Trends in cardiac CT utilization for patients with pediatric and congenital heart disease: A multicenter survey study.

BACKGROUND: The use of cardiac CT (CCT) has increased dramatically in recent years among patients with pediatric and congenital heart disease (CHD), but little is known about trends and practice pattern variation in CCT utilization for this population among centers. METHODS: A 21-item survey was created to assess CCT utilization in the pediatric/CHD population in calendar years 2011 and 2021. The survey was sent to all non-invasive cardiac imaging directors of pediatric cardiology centers in North America in September 2022. RESULTS: Forty-one centers completed the survey. In 2021, 98% of centers performed CCT in pediatric and CHD patients (vs. 73% in 2011), and 61% of centers performed >100 CCTs annually (vs. 5% in 2011). While 62% of centers in 2021 utilized dual-source technology for high-pitch helical acquisition, 15% of centers reported primarily performing CCT on a 64-slice scanner. Anesthesia utilization, use of medications for heart rate control, and type of subspecialty training for physicians interpreting CCT varied widely among centers. 50% of centers reported barriers to CCT performance, with the most commonly cited concerns being radiation exposure, the need for anesthesia, and limited CT scan staffing or machine access. 37% (11/30) of centers with a pediatric cardiology fellowship program offer no clinical or didactic CCT training for categorical fellows. CONCLUSION: While CCT usage in the CHD/pediatric population has risen significantly in the past decade, there is broad center variability in CCT acquisition techniques, staffing, workflow, and utilization. Potential areas for improvement include expanding CT scanner access and staffing, formal CCT education for pediatric cardiology fellows, and increasing utilization of existing technological advances.

Cardiac manifestations and outcomes of COVID-19 vaccine-associated myocarditis in the young in the USA: longitudinal results from the Myocarditis After COVID Vaccination (MACiV) multicenter study.

Background: We aimed to study the clinical characteristics, myocardial injury, and longitudinal outcomes of COVID-19 vaccine-associated myocarditis (C-VAM). Methods: In this longitudinal retrospective observational cohort multicenter study across 38 hospitals in the United States, 333 patients with C-VAM were compared with 100 patients with multisystem inflammatory syndrome in children (MIS-C). We included patients ≤30 years of age with a clinical diagnosis of acute myocarditis after COVID-19 vaccination based on clinical presentation, abnormal biomarkers and/or cardiovascular imaging findings. Demographics, past medical history, hospital course, biochemistry results, cardiovascular imaging, and follow-up information from April 2021 to November 2022 were collected. The primary outcome was presence of myocardial injury as evidenced by late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging. Findings: Patients with C-VAM were predominantly white (67%) adolescent males (91%, 15.7 ± 2.8 years). Their initial clinical course was more likely to be mild (80% vs. 23%, p < 0.001) and cardiac dysfunction was less common (17% vs. 68%, p < 0.0001), compared to MIS-C. In contrast, LGE on CMR was more prevalent in C-VAM (82% vs. 16%, p < 0.001). The probability of LGE was higher in males (OR 3.28 [95% CI: 0.99, 10.6, p = 0.052]), in older patients (>15 years, OR 2.74 [95% CI: 1.28, 5.83, p = 0.009]) and when C-VAM occurred after the first or second dose as compared to the third dose of mRNA vaccine. Mid-term clinical outcomes of C-VAM at a median follow-up of 178 days (IQR 114-285 days) were reassuring. No cardiac deaths or heart transplantations were reported until the time of submission of this report. LGE persisted in 60% of the patients at follow up. Interpretation: Myocardial injury at initial presentation and its persistence at follow up, despite a mild initial course and favorable mid-term clinical outcome, warrants continued clinical surveillance and long-term studies in affected patients with C-VAM. Funding: The U.S. Food and Drug Administration.

Myocardial Fibrosis in Congenital Heart Disease and the Role of MRI.

Progress in the field of congenital heart surgery over the last century can only be described as revolutionary. Recent improvements in patient outcomes have been achieved through refinements in perioperative care. In the current and future eras, the preservation and restoration of myocardial health, beginning with the monitoring of tissue remodeling, will be central to improving cardiac outcomes. Visualization and quantification of fibrotic myocardial remodeling is one of the greatest assets that cardiac MRI brings to the field of cardiology, and its clinical use within the field of congenital heart disease (CHD) has been an area of particular interest in the last few decades. This review summarizes the physical underpinnings of myocardial tissue characterization in CHD, with an emphasis on T1 parametric mapping and late gadolinium enhancement. It describes methods and suggestions for obtaining images, extracting quantitative and qualitative data, and interpreting the results for children and adults with CHD. The tissue characterization observed in different lesions is used to examine the causes and pathomechanisms of fibrotic remodeling in this population. Similarly, the clinical consequences of elevated imaging biomarkers of fibrosis on patient health and outcomes are explored. Keywords: Pediatrics, MR Imaging, Cardiac, Heart, Congenital, Tissue Characterization, Congenital Heart Disease, Cardiac MRI, Parametric Mapping, Fibrosis, Late Gadolinium Enhancement © RSNA, 2023.

Right Ventricular Strain in Patients With Ductal-Dependent Tetralogy of Fallot.

BACKGROUND: Right ventricular (RV) dysfunction is an independent predictor of poor outcomes in patients with tetralogy of Fallot (TOF), and global longitudinal strain (GLS) is a well-validated echocardiographic technique to measure RV function. Although trends in RV GLS have been examined in patients with TOF, they have not been studied specifically in those with ductal-dependent TOF, a group in which there is not a clear consensus on the best surgical strategy. The aim of this study was to assess the midterm trajectory of RV GLS in patients with ductal-dependent TOF, drivers of this trajectory, and differences in RV GLS between repair strategies. METHODS: This was a retrospective two-center cohort study of patients with ductal-dependent TOF who underwent repair. Ductal dependence was defined as being initiated on prostaglandin therapy and/or undergoing surgical intervention on or before 30 days of life. RV GLS was measured on echocardiography preoperatively, early after complete repair, and at 1 and 2 years of age. RV GLS was trended over time and compared between surgical strategies and with control subjects. Mixed-effects linear regression models were used to evaluate the factors associated with changes in RV GLS over time. RESULTS: Forty-four patients with ductal-dependent TOF were included in the study, of whom 33 (75%) underwent primary complete repair and 11 (25%) underwent staged repair. Complete TOF repair was performed at a median of 7 days in the primary-repair group and 178 days in the staged-repair group. RV GLS improved over time from post-complete repair echocardiography through 2 years of age (-17.4% [interquartile range, -15.5% to -18.9%] vs -21.5% [interquartile range, -18.0% to -23.3%], P < .001). However, compared with age-matched control subjects, patients had worse RV GLS at all time points. There was no difference in RV GLS between the staged and primary complete repair groups at 2-year follow-up. Shorter intensive care unit length of stay after complete repair was independently associated with improvement in RV GLS over time. Strain improved by 0.07% (95% CI, 0.01 to 0.12) for each fewer day in the intensive care unit (P = .03). CONCLUSIONS: RV GLS improves over time among patients with ductal-dependent TOF, though it is consistently reduced compared with control subjects, suggesting an altered deformation pattern in patients with ductal-dependent TOF. There was no difference in RV GLS between the primary- and staged-repair groups at midterm follow-up, suggesting that repair strategy is not a risk factor for worse RV strain in the mid postoperative period. A shorter complete-repair intensive care unit length of stay is associated with an improved trajectory of RV GLS.

Post-operative troponin levels and left ventricular function in patients with d-transposition of the great arteries following the arterial switch operation.

The aim of this study was to assess the significance of post-operative troponin levels as a surrogate for left ventricular (LV) dysfunction measured by global longitudinal strain (GLS) in patients with dextro-transposition of the great arteries (d-TGA) who undergo an arterial switch operation (ASO), and to explore the LV GLS recovery in the mid-term follow-up period. Seventy-eight neonates were included, of whom 41 had troponin-I measurements and 37 had troponin-T measurements. The primary outcome of LV GLS was assessed and compared with healthy controls at the pre-operative stage and time of discharge, 3 months, 6 months and 12 months of age. Secondary outcomes included deaths or transplantations and other clinical markers such as length of hospital stay. D-TGA patients had worse LV GLS post-operatively compared to age-matched controls (p < 0.01) which improved by 12 months of age (p = 0.53). No association was found between changes in troponin-I or troponin-T levels and LV GLS at the time of discharge (r = 0.4, p = 0.64 and r = -0.5, p = 0.91, respectively). In addition, there were no deaths or transplantations in this cohort over a period of 12 months. LV GLS appears to worsen in the early post-operative period for d-TGA patients who undergo neonatal ASO but this recovers through the first post-operative year. Troponin levels have limited value in predicting early or midterm LV dysfunction and recovery.

Cardiovascular Testing in the United States during the COVID-19 Pandemic: Volume Recovery and Worldwide Comparison.

Purpose: To characterize the recovery of diagnostic cardiovascular procedure volumes in U.S. and non-U.S. facilities in the year following the initial COVID-19 outbreak. Materials and Methods: The International Atomic Energy Agency (IAEA) coordinated a worldwide study called the IAEA Noninvasive Cardiology Protocols Study of COVID-19 2 (INCAPS COVID 2), collecting data from 669 facilities in 107 countries, including 93 facilities in 34 U.S. states, to determine the impact of the pandemic on diagnostic cardiovascular procedure volumes. Participants reported volumes for each diagnostic imaging modality used at their facility for March 2019 (baseline), April 2020, and April 2021. This secondary analysis of INCAPS COVID 2 evaluated differences in changes in procedure volume between U.S. and non-U.S. facilities and among U.S. regions. Factors associated with return to prepandemic volumes in the United States were also analyzed in a multivariable regression analysis. Results: Reduction in procedure volumes in April 2020 compared with baseline was similar for U.S. and non-U.S. facilities (-66% vs -71%, P = .27). U.S. facilities reported greater return to baseline in April 2021 than did all non-U.S. facilities (4% vs -6%, P = .008), but there was no evidence of a difference when comparing U.S. facilities with non-U.S. high-income country (NUHIC) facilities (4% vs 0%, P = .18). U.S. regional differences in return to baseline were observed between the Midwest (11%), Northeast (9%), South (1%), and West (-7%, P = .03), but no studied factors were significant predictors of 2021 change from prepandemic baseline. Conclusion: The reductions in cardiac testing during the early pandemic have recovered within a year to prepandemic baselines in the United States and NUHICs, while procedure volumes remain depressed in lower-income countries.Keywords: SPECT, Cardiac, Epidemiology, Angiography, CT Angiography, CT, Echocardiography, SPECT/CT, MR Imaging, Radionuclide Studies, COVID-19, Cardiovascular Imaging, Diagnostic Cardiovascular Procedure, Cardiovascular Disease, Cardiac Testing Supplemental material is available for this article. © RSNA, 2023.