CLINICOPATHOLOGICAL HETEROGENEITY IN HYPERTROPHIC CARDIOMYOPATHY WITHREGARD TO AGE, ASYMMETRIC SEPTAL HYPERTROPHY, AND CONCENTRIC HYPERTROPHY BEYOND THE PEDIATRIC AGE GROUP

Background.-To our knowledge, no histopathologic study of the differen ces between hypertrophic cardiomyopathy in different age groups or tha t contrasts the pathologic findings in the asymmetric septal hypertrop hy and concentric hypertrophy forms of hypertrophic cardiomyopathy has been published. Methods.-The clinicopathologic findings of younger (l ess than or equal to 60 years) (n = 35) and older (>60 years) (n = 20) patients with hypertrophic cardiomyopathy were assessed. Each group w as subdivided into groups of patients with asymmetric septal hypertrop hy or concentric hypertrophy. Results.-Among the young patients, asymm etric septal hypertrophy was more prevalent than concentric hypertroph y, whereas among the elderly patients, concentric hypertrophy was more common. Sudden death was prevalent only among the young. Most young p atients had a mirror-image endocardial fibrous septal plaque, whereas most elderly patients with concentric hypertrophy did not. Ventricular septal myocyte disarray and intramural coronary artery thickening wer e far more marked among the young with asymmetric septal hypertrophy t han the young with concentric hypertrophy and the elderly. Conclusions .-Key differences exist between younger and older patients with hypert rophic cardiomyopathy. Much higher degrees of ventricular disarray and intramural coronary artery disease were noted in younger patients wit h asymmetric septal hypertrophy compared to the elderly patients and t he younger patients with concentric hypertrophy.