Myocarditis

GENERAL PRINCIPLES

• Myocarditis is an inflammatory disease of the myocardium often but not always caused by an infectious agent.

• Causes of infectious myocarditis include viruses, bacteria, rickettsia, fungi, and parasites.

• Viruses are the most frequent etiologic organism and include enteroviruses (coxsackie B and echovirus), adenovirus, human herpesvirus 6, parvovirus B19, and many others.

Clinical Presentation

Chest pain, elevated cardiac enzymes (e.g., troponin), fever, and diffuse ST-segment abnormalities on EKG are the classical manifestations of infectious myocarditis.

DIAGNOSIS

• The diagnostic “gold standard” is endomyocardial biopsy for histological, immunological, and immunohistochemical criteria, including specific viral PCR.

• Cardiac MRI can be useful for diagnosis and monitoring of disease progression.

• Viral culture and serologic testing are rarely helpful.

TREATMENT

Supportive care is the mainstay of treatment. NSAIDs should be avoided. The role of IV immunoglobulin and antiviral agents in viral-mediated myocarditis remains anecdotal.¹⁴