Concurrent Acute Myocarditis in Monozygotic Twins: A Case Report with Similar CMR Findings

Abstract

Introduction: Genetic influences have been implicated in the pathogenesis of myocarditis. This case report describes monozygotic twins who presented simultaneously with acute myocarditis and exhibited similar patterns of cardiac involvement on imaging, representing a rare observation among adult twins. Case Presentation: A pair of 18-year-old monozygotic male twins were admitted concurrently with left-sided chest pain, dyspnea, and palpitations after a recent journey and flu-like symptoms. Twin 1 (IV:1) had a left ventricular ejection fraction (LVEF) of 55%, with mildly reduced strain in the inferolateral wall. T2-weighted cardiac magnetic resonance (CMR) imaging, including short tau inversion recovery (STIR), showed localized inflammation in the inferolateral wall; late gadolinium enhancement (LGE) suggested myocardial injury (edema and/or early fibrosis) in the basal and mid posterolateral segments. Twin 2 (IV:2) also had an LVEF of 55%. T2-weighted CMR, including STIR, indicated inflammation in the apicoanterior and apicolateral segments, with corresponding LGE in the same regions. Conclusions: Although shared environmental exposure remains the most likely explanation for the simultaneous presentation, this case highlights the importance of considering genetic evaluation in similar presentations involving twins. Genetic testing, including testing of desmosomal genes such as desmoplakin (DSP), is recommended in future cases of myocarditis involving twins.