Antimitochondrial autoantibodies in myocardial hypertrophy: Comparison between hypertrophic cardiomyopathy, hypertensive heart disease, and athlete's heart

Antimitochondrial autoantibodies (AMA) were tested by indirect immunofluorescence in three groups of subjects with different types of myocardial hypertrophy: 35 patients affected with hypertrophic cardiomyopathy (HC), 20 patients with cardiac hypertrophy secondary to essential hypertension, and 35 active endurance athietes with exercise-induced left ventricular hypertrophy. Forty-two healthy subjects served as a control group. Left ventricular hypertrophy was considered a left ventricular mass (LVM) echocardiographically calculated (Devereux formula), exceeding 244 gm or a LVM index exceeding 122 gm/m 2 (greate than 2 SD from a previously studied normal population). AMA were found in 15 of 35 (43%) patients with HC and in 6 of 20 (30%) patients with hypertensive heart disease ( p < 0.01); in contrast, AMA were not present in the sera of athletes or in the sera of controls. Although the significance of AMA in subjects with pathologic myocardial hypertrophy has not yet been established, their absence in the sera of athletes strengthens the opinion that cellular changes, as a compensatory response of the myocardium to a work overload, have a physiologic fashion in these cases. Moreover, identification of AMA in the sera of athletes with disproportionate severe left ventricular hypertrophy of uncertain origin may be helpful to ensure a single diagnosis.