Utility of cardiac MRI in paediatric myocarditis.

BACKGROUND: The diagnostic role of cardiac MRI in myocarditis is evolving, however with extremely limited data in paediatrics. The goal of this study was to assess the utility of cardiac MRI in paediatric myocarditis and present a new prognostic score for risk stratification.

METHOD: The present study is a retrospective investigation of children with a clinical diagnosis of myocarditis, including analysis of demographics, clinical presentation, diagnostic studies, including cardiac MRI, and outcomes.

RESULTS: A total of 44 patients met the inclusion criteria, of whom 20 had undergone cardiac MRI. Patients who underwent cardiac MRI were older (median 15.6 versus 11.1 years, p=0.004), had a shorter length of hospital stay (median 4.0 versus 12.5 days, p=0.004), had overall less-severe illness at presentation as evidenced by a higher left-ventricular ejection fraction on echocardiography, had lower peak brain-type natriuretic peptide, were less likely to require advanced mechanical support, and were less likely to experience cardiac death or transplant. In patients who had undergone cardiac MRI, the most common findings were increased early gadolinium enhancement (n=9) or late gadolinium enhancement (n=9). Cardiac MRI findings did not predict a worse outcome. Independent predictors of the need for heart-failure medications at 1-year follow-up included inotrope requirement, extracorporeal membrane oxygenator requirement, and antiarrhythmic requirement at presentation (p<0.05).

CONCLUSION: In paediatric myocarditis, cardiac MRI is not used uniformly, has a low yield, and does not predict worse outcomes. Future research should evaluate clinical decision-making and the cost-benefit analysis of cardiac MRI in the diagnosis of paediatric myocarditis.