Macroscopic and microscopic autopsy findings in a patient with rheumatic heart disease.

(A) Photomacrograph showing a notably thickened left atrial endocardium with fibrotic lesions (arrowheads). (B) Photomicrograph of a left atrial myocardium section stained with Masson’s trichrome. The left atrial wall shows diffuse interstitial and replacement fibrosis with endocardial thickening (*). (C) High-power field image of the square frame in (B) stained with hematoxylin and eosin. Lymphocytes infiltrating predominantly into the myocardial interstitium with replacement fibrosis (arrowheads). (D) Same as the (C) area stained with Masson’s trichrome showing myofibrillar degeneration (arrowheads).