Background and objectives. Acute myocarditis may clinically present like an acute coronary syndrome (ACS) and lead to fatal consequences if not diagnosed timely and accurately. Cardiovascular magnetic resonance (CMR) allows to diagnose acute myocarditis non-invasively and is widely used in children and adults with suspected myocarditis. Surprisingly, comparative data on CMR findings in children vs. adults with acute myocarditis are scarce. We aimed to compare the extent and pattern of acute myocardial injury caused by acute myocarditis using CMR in paediatric vs. adult patients.
Methods. Based on a mono-centric retrospective analysis using strict and mandatory clinical, laboratory and CMR criteria for the diagnosis of ACS-like myocarditis, N=18 paediatric (group A) and N=43 adult patients (group B) with acute myocarditis were identified between 2013 and 2025. The respective CMR studies comprised (amongst others) cine-imaging for functional analyses as well as late-gadolinium-enhancement (LGE)-imaging for structural assessment of the myocardium.
Results. The mean age was 15yrs (range 14-17yrs) in group A vs. 29yrs (range 18-54yrs) in group B (p<0.001). Significant ECG abnormalities were observed in 13 (72%) patients of group A compared to 28 (65%) patients in group B (p=NS). Higher values for cardiac biomarkers were measured in the paediatric group: the mean creatine kinase (CK) level was 1,031 U/l in group A vs. 608 U/l group B (p = 0.006); the mean maximum high-sensitive troponin T (hs-TnT) level was 1,600 ng/l in group A vs. 1,023 ng/l in group B (p = 0.024).
Volumetric CMR analyses revealed similar findings – within normal range – between both groups regarding LV-EF, LV-EDV, RV-EF and RV-EDV. There was only a mild trend to a higher percentage of an impaired LV systolic function and/or presence of wall motion abnormalities in the paediatric group: 3 (17%) patients from group A compared to 6 (14%) in group B (p = 0.07).
Mean LGE extent was 10.8 % in group A compared to 10.5 % in group B (p = 0.16). The most common LGE pattern in both groups was a non-ischemic (subepicardial/intramural) pattern in the LV lateral wall (13 (72 %) in group A vs. 26 (61 %) group B; p = 0.45) followed by a multifocal pattern affecting the septal as well as lateral wall (3 (17 %) in group A vs. 11 (26 %) in group B; p = 0.43) – without any substantial differences between both groups. One paediatric patient (6 %) and three adult patients (7 %) demonstrated a “ring-like” LGE pattern (p = 0.82). Concomitant acute pericarditis was seen in 7 (39 %) children from group A and 11 (26 %) adults from group B (p = 0.46).
Conclusion. The maximal value of cardiac enzymes was higher in paediatric patients with acute myocarditis compared to adult ones. However, this difference in serum biomarkers was not accompanied by any functional and/or structural differences regarding the extent and/or pattern of myocardial injury based on comprehensive CMR analyses.
