What is the gold standard for diagnosing myocarditis?

The gold standard for diagnosing myocarditis is endomyocardial biopsy. This procedure involves the removal of a small piece of heart tissue, which can then be analyzed for inflammation and other specific signs of myocarditis. Histological examination of the biopsy can reveal lymphocytic infiltration and other changes characteristic of myocarditis, confirming the diagnosis.

Although other modalities such as echocardiography, MRI of the heart, and cardiac catheterization play important roles in evaluating patients with suspected myocarditis, they do not provide definitive confirmation of the diagnosis. Echocardiograms can show functional changes in the heart, while cardiac MRI might reveal inflammation and edema in the myocardium. Cardiac catheterization can assess coronary artery conditions but typically does not provide the specific histopathological information required to definitively diagnose myocarditis. Thus, endomyocardial biopsy remains the critical diagnostic tool in this context.