The morphological progression of viral myocarditis

Area of Science:

• Cardiology
• Pathology

Background:

• Acute myocarditis is an inflammation of the heart muscle.
• Dilated cardiomyopathy is a condition characterized by enlargement and weakening of the left ventricle.

Purpose of the Study:

• To investigate the morphological progression from acute myocarditis to dilated cardiomyopathy.
• To assess the impact of immunosuppressive treatment on this progression.

Main Methods:

• Serial endomyocardial biopsies were performed on 20 patients diagnosed with myocarditis.
• Patients' ages ranged from 6 months to 62 years, with biopsy intervals of 1 month to 2 years.
• Fifteen patients received immunosuppressive drugs; 5 did not.

Main Results:

• In all patients, inflammatory infiltrates decreased, but myocardial hypertrophy and interstitial fibrosis increased.
• Eight patients showed morphological changes consistent with dilated cardiomyopathy.
• Immunosuppressive treatment did not consistently prevent progression to dilated cardiomyopathy; some treated patients worsened, while some untreated patients stabilized spontaneously.

Conclusions:

• Dilated cardiomyopathy can be a morphological end result of acute myocarditis.
• Progression from acute myocarditis to dilated cardiomyopathy is not inevitable.
• Immunosuppressive therapy may not prevent the progression of myocarditis to dilated cardiomyopathy.