Myocarditis is an inflammation of the myocardium, the middle muscular layer of the heart. This inflammation can manifest with various symptoms such as chest pain, shortness of breath, or rapid or irregular heart rhythms. The heart muscle constitutes a significant portion of the heart and, like other muscles in the body, is susceptible to inflammation. Myocarditis can be caused by bacterial, viral, or fungal infections, as well as autoimmune diseases. Constituting approximately 25% of heart muscle diseases, myocarditis leads to damage in heart muscle cells.