Hidden and Atypical Presentations of Myocarditis in Sudden Cardiac Death: A Narrative Review

Myocarditis is an inflammatory disease of the heart muscle, presenting from asymptomatic cases to sudden cardiac death. Its diagnosis is challenging, especially when classic cardiac symptoms are absent presents with unusual manifestations. Recognition of these unusual manifestations is essential to prevent sudden death and increase clinical awareness.

This narrative review was conducted to summarize the evidence on myocarditis with occult and nonclassical manifestations and its role in sudden cardiac death. A systematic search was performed in PubMed, Scopus, Embase, Cochrane Library, and Google Scholar for studies published between 2000 and 2025. Search terms included English language, such as "myocarditis," "sudden cardiac death," "atypical presentation," "silent myocarditis," and "gastrointestinal symptoms".

A total of 10 studies were included and analyzed, focusing on clinical characteristics, nonclassical presentations, diagnostic findings, and outcomes. Myocarditis can be insidious and asymptomatic in young patients and increases the risk of sudden cardiac death. The diagnosis of these cases is often only possible after cardiac arrest or autopsy. In addition, myocarditis may present with nonclassical symptoms, particularly gastrointestinal symptoms, delaying diagnosis.

Myocarditis, whether asymptomatic or with nonclassical manifestations such as gastrointestinal symptoms, can be a serious health threat, especially in young people, and in some cases can cause sudden cardiac death. Evidence suggests that many of these deaths in apparently healthy individuals are due to undiagnosed myocarditis. Early recognition and attention to nonclassical symptoms are essential to prevent sudden death and improve patient management.