Cardiovascular magnetic resonance serves as a useful tool in diagnosing myocarditis. Current adult protocols are yet to be validated for children; thus, it remains unclear if the methods used can be applied with sufficient image quality in children. This study assesses the use of cardiovascular magnetic resonance in children with suspected myocarditis.Image data from clinical cardiovascular magnetic resonance studies performed in children enrolled in Mykke between June 2014 and April 2019 were collected and analysed. The quality of the data sets was evaluated using a four-point quality scale (4: excellent, 3: good, 2: moderate, 1: non-diagnostic).A total of 102 patients from 9 centres were included with a median age (interquartile range) of 15.4(10.7-16.6) years, 137 cardiovascular magnetic resonance studies were analysed. Diagnostic image quality was found in 95%. Examination protocols were consistent with the original Lake Louise criteria in 58% and with the revised criteria in 35%. Older patients presented with better image quality, with the best picture quality in the oldest age group (13-18 years). Sedation showed a negative impact on image quality in late gadolinium enhancement and oedema sequences. No such correlation was seen in cardiac function assessment sequences. In contrast to initial scans, in follow-up examinations, the use of parametric mapping increased while late gadolinium enhancement and oedema sequences decreased.Cardiovascular magnetic resonance protocols for the assessment of adult myocarditis can be applied to children without significant constraints in image quality. Given the lack of specific recommendations for children, cardiovascular magnetic resonance protocols should follow recent recommendations for adult cardiovascular magnetic resonance.
Background: Heart failure (HF) due to myocarditis might not respond in the same way to standard therapy as HF due to other aetiologies. The aim of this study was to investigate the value of endomyocardial biopsies (EMB) for clinical decision-making and its relation to the outcome of paediatric patients with myocarditis.Methods: Clinical and EMB data of children with myocarditis collected for the MYKKE-registry between 2013 and 2020 from 23 centres were analysed. EMB studies included histology, immunohistology, and molecular pathology. The occurrence of major adverse cardiac events (MACE) including mechanical circulatory support (MCS), heart transplantation, and/or death was defined as a combined endpoint.Results: Myocarditis was diagnosed in 209/260 patients: 64% healing/chronic lymphocytic myocarditis, 23% acute lymphocytic myocarditis (AM), 14% healed myocarditis, no giant cell myocarditis. The median age was 12.8 (1.4-15.9) years. Time from symptom-onset to EMB was 11.0 (4.0-29.0) days. Children with AM and high amounts of mononuclear cell infiltrates were significantly younger with signs of HF compared to those with healing/chronic or healed myocarditis. Myocardial viral DNA/RNA detection had no significant effect on outcome. The worst event-free survival was seen in patients with healing/chronic myocarditis (24%), followed by acute (31%) and healed myocarditis (58%, p=0.294). A weaning rate of 64% from MCS was found in AM.Conclusions: EMB provides important information on the type and stage of myocardial inflammation and supports further decision-making. Children with fulminant clinical presentation, high amounts of mononuclear cell infiltrates or healing/chronic inflammation and young age have the highest risk for MACE.
Myocarditis represents one of the most common causes of Sudden Cardiac Death in children. Myocardial involvement during a viral infection is believed to be higher as a consequence of intensive exertion. Recommendations for return to sports are based on cohort and case studies only. This study aims to investigate the relationship between physical activity and myocarditis in the young.Every patient in the MYKKE registry fulfilling criteria for suspicion of myocarditis was sent a questionnaire regarding the physical activity before, during and after the onset of myocarditis.This study is a subproject within the MYKKE registry, a multicenter registry for children and adolescents with suspected myocarditis. The observation period for this analysis was 93 months (September 2013-June 2021). Anamnestic, cardiac magnetic resonance images, echocardiography, biopsy and laboratory records from every patient were retrieved from the MYKKE registry database.58 patients (mean age 14.6 years) were enrolled from 10 centers. Most patients participated in curricular physical activity and 36% in competitive sports before the onset of myocarditis. There was no significant difference of heart function at admission between the physically active and inactive subjects (ejection fraction of 51.8 ± 8.6% for the active group vs. 54.4 ± 7.7% for the inactive group). The recommendations regarding the return to sports varied widely and followed current guidelines in 45%. Most patients did not receive an exercise test before returning to sports.Sports before the onset of myocarditis was not associated with a more severe outcome. There is still a discrepancy between current literature and actual recommendations given by health care providers. The fact that most participants did not receive an exercise test before being cleared for sports represents a serious omission.
Background/Objectives: Risk assessment in pediatric myocarditis is challenging, particularly when left ventricular ejection fraction (LVEF) is preserved. This study aimed to evaluate LV myocardial deformation using speckle-tracking echocardiography (STE)-derived longitudinal +strain (LS) and assessed its diagnostic and prognostic value in children with myocarditis. Methods: Retrospective STE-derived layer-specific LV LS analysis was performed on echocardiograms from patients within the multicenter, prospective registry for pediatric myocarditis “MYKKE”. Age- and sex-adjusted logistic regression and ROC analysis identified predictors of cardiac arrhythmias (ventricular tachycardia, ventricular fibrillation, atrioventricular blockage III°) and major adverse cardiac events (MACE: need for mechanical circulatory support (MCS), cardiac transplantation, and/or cardiac death). Results: Echocardiograms from 175 patients (median age 15 years, IQR 7.9–16.5 years; 70% male) across 13 centers were included. Cardiac arrhythmias occurred in 36 patients (21%), and MACE in 28 patients (16%). Impaired LV LS strongly correlated with reduced LVEF (r > 0.8). Impaired layer-specific LV LS, reduced LVEF, LV dilatation, and increased BSA-indexed LV mass, were associated with the occurrence of MACE and cardiac arrhythmias. In patients with preserved LVEF, LV LS alone predicted cardiac arrhythmias (p < 0.001), with optimal cutoff values of −18.0% for endocardial LV LS (sensitivity 0.69, specificity 0.94) and –17.0% for midmyocardial LV LS (sensitivity 0.81, specificity 0.75). Conclusions: In pediatric myocarditis, STE-derived LV LS is not only a valuable tool for assessing systolic myocardial dysfunction and predicting MACE but also identifies patients at risk for cardiac arrhythmias, even in the context of preserved LVEF.
