Hypertrophic Cardiomyopathy (HCM)
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This micrograph is a transmural transverse section of the interventricular septum of a heart with hypertrophic cardiomyopathy (note the endocardium present on both sides of the section (top and bottom)¬. The dashed lines show the variation in direction of the myocyte fascicles (fascicular disarray). The green circle demonstrates an area of myocyte disarray with stellate looking myocytes which also show disarray of the sarcomeres as evidenced by the crisscrossing striations of the myofibrils in the sarcoplasm of the myocytes. The intramural coronary arteries are often thickened and even dysplastic in cases of hypertrophic cardiomyopathy . These areas of dysplastic changes are commonly present and are referred to as; small intramural coronary artery dysplasia (SICAD). An area like this is highlighted in the green oval. The dysplastic coronary disease produces ischemic injury that results in necrosis of areas of the myocardium which in turn form areas of replacement fibrosis (white dotted line) as they heal.
