Q wave in paediatric myocarditis: an underinvestigated, readily available prognostic factor

Abstract

Background Myocarditis is an uncommon disease in children with potentially fatal consequences. An electrocardiogram (ECG) change seen in myocarditis is pathological Q wave. Pathological Q wave is linked to permanent damage and myocardial death in several cardiac diseases. We investigated the significance of pathological Q waves in children with acute myocarditis (AM). Methods This retrospective observational study analysed the data of 59 children with AM admitted to our hospital between January 2016 and July 2021. They were divided into Q wave and non-Q wave myocarditis groups. Patients’ laboratory data, echocardiography, treatment and hospital outcome were analysed. Results Patients were 64.4% male and had a median age of 6 years and 9 months. Pathological Q waves were found in 52.5% of the patients. Q wave myocarditis group had higher troponin I values (499 vs. 145 ng/L, p = 0.011) and longer hospital stays (13 vs. 9 days, p = 0.020) than the non-Q wave group. They also required higher doses of inotropic or vasoactive drugs. 61.3% of Q wave patients needed mechanical ventilation compared to 35.7% of non-Q wave patients (p = 0.069). All the patients who died or discharged with an LVEF < 30% belonged to the Q wave group. Conclusion Q wave in AM warrants close monitoring and intensive treatment as it accompanies more severe complications and poorer outcomes. This readily available ECG finding can be a clue to prognoses of AM patients. Further research with larger populations is needed to better understand Q wave prognostic accuracy and its potential role in guiding more expensive treatments.