Sections through the heart show myofiber disarray with hypertrophic nuclei and a moderate to focally severe interstitial fibrosis. This is more prominent in sections 1J and 1K, both from the left ventricle. The myocytes also demonstrate vacuolized cytoplasm. The fibrotic areas and the interstitium contain a mild mononuclear cell infiltrate. In section 1J (left ventricle) there is a fresh mural thrombus and a previous biopsy site, represented by fibroblastic proliferation and hemosiderin- laden macrophages. Section 1G, from the right ventricle, contains a Quilty lesion. The coronary arteries exhibit obliterative changes corresponding to the grossly described occlusions and are most severe in section 1D from the right coronary artery with extensive involvement of the left anterior descending artery. The changes comprise complicated atherosclerosis and focal foam cell deposition with a mild to moderate mural mononuclear inflammation. The smaller vessels (intramyocardial branches) are characterized by mild fibro- intimal hyperplasia, focal cholesterol clefts deposition and in one area a larger vessel shows fibro-obliterative intimal thickening. No viral inclusions are appreciated.