Myocarditis, an inflammatory disease of the heart muscle, most often caused by an autoimmune process or viral infection is an essential cause of dilated cardiomyopathy worldwide and also, one of the most challenging diagnosis in cardiology today. Myocarditis of either viral or an autoimmune cause can lead to fatal, life-threatening arrhythmias and/or cardiogenic shock which in some patients, may progress to chronic myocarditis and dilated cardiomyopathy affecting both short- and long-term prognostic outcomes where rapid elimination of the infectious agent and rapid withholding changes of the inflammatory process in the myocardium are too small. Conceptually, the pathogenesis of myocarditis can be sub-divided into three stages: an initial viral proliferation phase, immunologic response and inflammation phase, and finally, a myocardial remodeling and fibrotic phase. Due to the long-term consequences, and the broad spectrum of factors (infectious, immunologic, toxic, among others) causing/leading inflammatory heart muscle diseases, it is imperative that diagnosis and appropriate treatments are done early. At present, due to the insensitivity of traditional diagnostic tests, no diagnostic gold standard is generally accepted, leading to the search for new diagnostic approaches/methods, resulting in the emergence of new molecular diagnostic techniques, and a more detailed immunohistochemical analysis of endomyocardial biopsies. Be it as it may, this chapter aims to discuss the unresolved issues faced with myocarditis (viral and autoimmune) and cardiomyopathy (Infective inflammatory), their relationship as single entities, associated autoimmune processes, old and new treatment options available for patients, recently proposed new general diagnostic approaches, diagnostic gold standard, setbacks, and pitfalls.
Keywords: Autoimmune mechanism, Biopsy, Cytokine, Consensus, Cardiomyopathy, Contrast media, Cardiovascular magnetic resonance imaging, Diagnosis, Endomyocardial fibrosis, Heart failure, Inflammation, Infective heart disease, Immunosuppression, Immunomodulation, Immunoadsorption, Myocarditis, Management, Polymerase chain reaction, Pediatric Cardiology, Therapy, Virus.