127 - Factors Identifying Children And Young Adults At Low Risk For Myocarditis

Poster Number: 127
Publication Number: 127.1486

Background: Myocarditis is a rare condition with numerous etiologies and wide spectrum of clinical presentation. There is insufficient evidence to justify the use of any single test to screen for myocarditis in children, leaving much clinical uncertainty as to the best approach to work up and refer children with symptoms of myocarditis in the emergency department.

Objective: To derive a prediction rule for pediatric myocarditis.

Design/Methods: In this case-control study, we retrospectively evaluated patients who presented to the emergency department of a pediatric hospital between 2010-2021 and underwent troponin testing for clinical suspicion for myocarditis. Case patients were diagnosed with myocarditis based on the American Heart Association classification system and confirmed by cardiologist records review. All other patients were deemed control patients and were randomly matched to cases in a 2:1 fashion. Demographic, clinical, and outcome data were abstracted from patient charts. A prediction rule was derived using logistic regression with forward selection (p-value stopping >0.05).

Results: We identified 93 case patients and 202 control patients. The prediction rule identified three significant variables: chest pain (adjusted odds ratio [aOR] 3.5, 95% CI 1.8 to 7.0), reported or measured fever (aOR 1.7, 95% CI 1.0 to 3.1) and atrioventricular (AV) conduction delays or ST segment changes (aOR 2.6, 95% CI 1.4 to 4.7). The sensitivity, calculated as the proportion of cases with at least one of the three predictors identified was 97% (CI 0.92 to 0.99). The rule had a specificity of 13% (CI 0.09 to 0.19). Blood work results were not included in the rule in an effort to identify a low-risk population in which further work up including venipuncture or cardiology consult could be avoided. However, an elevated troponin T (cutoff of >0.045 ng/mL) was found to have a high OR of >700 (CI 101.0 to 5290.0) for the outcome of myocarditis with a sensitivity of 93% (CI 0.864 to 0.975) and a specificity of 97% (CI 0.936 to 0.989). (Figure 1).

Conclusion(s): The prediction rule developed can help identify children at low risk for myocarditis and therefore avoid troponin testing and/or further evaluation including cardiology consult or cardiac imaging. Specificity was insufficient to rule in myocarditis without additional consideration. Troponin discriminates myocarditis well.