Prevalence and Pathophysiology
Idiopathic hypertrophic subaortic stenosis (IHSS) is relatively com¬mon in the elderly. A disproportionate septal thickening narrows the left ventricular outflow tract. Hypertrophic cardiomyopathy may also

occur without asymmetric septal hypertrophy; mitral annular calcifica¬tion may displace the mitral valve anteriorly, producing an outflow gradient. Abnormal ventricular compliance elevates the ventricular di¬astolic pressure, with a resultant increase in left atrial volume and pres¬sure and pulmonary venous congestion. Hypertrophic cardiomyopathy occurs more often in women and has a more favorable prognosis in older patients than in younger ones, with less likelihood of sudden car¬diac death