How accurate is an echocardiogram at diagnosing myocarditis or pericarditis?

An echocardiogram can show changes that are strongly suggestive of myocarditis but strictly speaking a tissue diagnosis is needed for a definitive diagnosis. I think a physician using a stethoscope can diagnose acute percarditis better than an echo can. If the echo shows fluid within the pericardial sac, it is suggesive of pericarditis. Constrictive pericarditis, a chronic form, can be diagnosed