[Echocardiographic observation of appearance and progression of mitral annular calcification in a patient with familial obstructive hypertrophic cardiomyopathy].
A 37-year-old man with familial hypertrophic obstructive cardiomyopathy (HOCM) developed mitral annular calcification (MAC) during the follow-up period. At the age of 23 years, a systolic murmur and electrocardiographic abnormality including giant T wave inversion were detected incidentally. His elder brother also had HOCM. Catheterization disclosed a left ventricular outflow pressure gradient of 25 mmHg and thickened interventricular septum. Echocardiography showed asymmetric septal hypertrophy and systolic anterior motion of the mitral valve. The patient was followed up by repeated echocardiography from age 37 years and the onset of MAC (2 mm in thickness) was found at age 48 years. One year later, the MAC had progressed markedly (5 mm) without other remarkable changes in the M-mode echocardiogram, except mitral regurgitation (at age 41 years), left ventricular apical as well as posterior wall hypertrophy (age 43 years) and left atrial enlargement (age 46 years). The left ventricular inflow velocity at the atrial contraction period decreased significantly concomitantly with MAC. MAC is a rare complication in young and middle aged patients. The onset and progression of MAC is still obscure in HOCM. This patient showed that sudden onset and rapid progression of MAC can occur in young patients with HOCM.