| – |
Viruses are the most common cause of myocarditis in economically advanced countries.
|
| – |
Enteroviruses and adenoviruses are the most common etiologic agents.
|
| – |
Viral myocarditis is a triphasic process. Phase 1 is the period of active viral replication in the myocardium during which
the symptoms of myocardial damage range from none to cardiogenic shock. If the disease process continues, it enters phase
2, which is characterized by autoimmunity triggered by viral and myocardial proteins. Heart failure often appears for the
first time in phase 2. Phase 3, dilated cardiomyopathy, is the end result in some patients. Diagnostic procedures and treatment
should be tailored to the phase of disease.
|
| – |
Viral myocarditis is a significant cause of dilated cardiomyopathy, as proved by the frequent presence of viral genomic material
in the myocardium, and by improvement in ventricular function by immunomodulatory therapy.
|
| – |
Myocarditis of any etiology usually presents with heart failure, but the second most common presentation is ventricular arrhythmia.
As a result, myocarditis is one of the most common causes of sudden death in young people and others without preexisting structural
heart disease.
|
| – |
Myocarditis can be definitively diagnosed by endomyocardial biopsy. However, it is clear that existing criteria for the histologic
diagnosis need to be refined, and that a variety of molecular markers in the myocardium and the circulation can be used to
establish the diagnosis.
|
| – |
Treatment of myocarditis has been generally disappointing. Accurate staging of the disease will undoubtedly improve treatment
in the future. It is clear that immunosuppression and immunomodulation are effective in some patients, especially during phase
2, but may not be as useful in phases 1 and 3. Since myocarditis is often selflimited, bridging and recovery therapy with
circulatory assistance may be effective. Prevention by immunization or receptor blocking strategies is under development.
|
| – |
Giant cell myocarditis is an unusually fulminant form of the disease that progresses rapidly to heart failure or sudden death.
Rapid onset of disease in young people, especially those with other autoimmune manifestations, accompanied by heart failure
or ventricular arrhythmias, suggests giant cell myocarditis.
|
| – |
Peripartum cardiomyopathy in economically developed countries is usually the result of myocarditis.
|