Histopathological analysis of abnormal electrocardiographic findings in hypertrophic cardiomyopathy With biopsied ventricular myocardium.

To clarify the relationship between electrocardiographic abnor malities and the histopathology of hypertrophic cardiomyopathy (HCM), 43 cases of HCM were studied electrocardiographically observing 1) abnormal Q waves, 2) QRS axis and voltages, 3) depth of negative P waves in V1, 4) giant negative T waves and 5) degree of ST segment depression. Each biopsied specimen was checked microscopically for 1) hypertrophy, 2) disarray and 3) fibrosis. Hypertrophy was graded from (0) to (3+) by the mean value of the shortest transverse diameters of at least 30 myocytes under hematoxylin-eosin stain. Disarray was graded from (0) to (3+) according to the degree of disarrangement of the myocytes under phosphotungstic acid-hematoxylin stain. Fibrosis was graded from (0) to (3+) by the % area counting method under Malloryazan stain. Multiple abnormal Q waves were associated with fibrosis in the presence of hypertrophy (p<0.01). HCM with SV1+RV5-6<35 mm had significantly more advanced fibrosis (p<0.001) and disarray (p<0.01) than HCM with SV1+RV5-6≥35 mm. The depth of the negative P in V1 reflected the degree of hypertrophy, disarray and fibrosis in HCM. HCM with giant negative T waves and ST segment depression (≥ 2 mm) had significantly milder fibrosis (p<0.01) and milder disarray (p<0.05) in the presence of hypertrophy.