In 1998, the Dallas criteria were established, allowing standardized diagnosis of myocarditis by endomyocardial biopsy (tissue samples taken from the inner surface of the heart muscle (myocardium)).
| First endomyocardial biopsy |
| Active myocarditis |
- Myocytolysis (disintegration of muscle cells) and myocyte necrosis (death of muscle cells)
- Lymphomonocytic infiltrate (pathologic: >5 lymphocytes/severe enlargement (400-fold)).
- Interstitial edema (fluid accumulation (edema) in the interstitial tissue space).
|
| Borderline Myocarditis |
- Only sparse lymphocytic infiltrate without evidence of necrosis
|
| Control biopsy |
| Persistent myocarditis |
- Continued myocyte necrosis and inflammation.
|
| Decreasing myocarditis |
- Decrease in lymphomonocytic infiltrate.
|
| Healed myocarditis |
- No myocytolysis and no myocyte necrosis.
- No lymphomonocytic infiltration
|
