Analysis of shape and motion of the mitral annulus in subjects with and without cardiomyopathy by echocardiographic 3-dimensional reconstruction

The shape and dynamics of the mitral annulus of 10 patients without heart d isease (controls), 3 patients with dilated cardiomyopathy, and 5 patients w ith hypertrophic obstructive cardiomyopathy and normal systolic function we re analyzed by transesophageal echocardiography and 3-dimensional reconstru ction. Mitral annular orifice area, apico-basal motion of the annulus, and nonplanarity were calculated over time. Annular area was largest in end dia stole and smallest in end systole. Mean areas were 11.8 +/- 2.5 cm(2) (cont rols), 15.2 +/- 4.2 cm(2) (dilated cardiomyopathy), and 10.2 +/- 2.4 cm(2) (hypertrophic cardiomyopathy) (P = not significant). After correction for b ody surface, annuli. from patients with normal left ventricular function we re smaller than annuli from patients with dilated cardiomyopathy (5.9 +/- 1 .2 cm(2)/m(2) vs 7.7 +/- 1.0 cm(2)/m(2); P < .02). The change in area durin g the cardiac cycle showed significant differences: 23.8% +/- 5.1% (control s), 13.2% +/- 2.3% (dilated cardiomyopathy), and 32.4% +/- 7.6% (hypertroph ic cardiomyopathy) (P < .001). Apico-basal motion was highest in controls, followed by those with hypertrophic obstructive and dilated cardiomyopathy (1.0 +/- 0.3 cm, 0.8 +/- 0.2 cm, 0.3 +/- 0.2 cm, respectively; P < .01). Vi sual inspection and Fourier analysis showed a consistent pattern of anteros eptal and posterolateral elevations of the annulus toward the left atrium. In conclusion, although area changes and apico-basal motion of the mitral a nnulus strongly depend on left ventricular systolic function, nonplanarity is a structural feature preserved throughout the cardiac cycle in all three groups.