Mitral valve in hypertrophic cardiomyopathy: a three-dimensional transesophageal study.

BACKGROUND: It is reported that the mitral valve (MV) in hypertrophic cardiomyopathy (HCM) has structural abnormalities. PURPOSE: To assess the MV in HCM patients using Three-Dimensional Transesophageal Echocardiography (3DTEE). METHODS: Transthoracic and 3DTEE studies focused on the mitral valve were performed prospectively in 21 HCM patients with obstruction (Group I), 37 HCM patients without obstruction (Group II) and 28 controls (Group III). RESULTS: The aortomitral angle was less obtuse in groups I and II compared with group III (104.6 ± 6.7° vs 107.6 ± 8.5° vs 112.9 ± 3.2°, p < 0.001) and the annulus height was larger (11.6 ± 1.3 mm vs 11.6 ± 2 mm vs 9.3 ± 1.1 mm, p < 0.001). Patients in group I compared with groups II and III had increased ratio of anterior leaflet length to left ventricular outflow tract (LVOT) diameter (1.9 ± 0.1 vs 1.7 ± 0.3 vs 1.3 ± 0.1, p < 0.05) and anterior displacement of the coaptation line as showed by the reduced ratio of anterior to posterior leaflet length in the projection plane (1.7 ± 0.4 mm vs 2.2 ± 0.7 mm vs 2.4 ± 0.7 mm, p < 0.05). In groups I and II there was a positive correlation between the MV annulus height and the presence of non-sustained ventricular tachycardia (rs = 0.25, p < 0.05). CONCLUSION: The MV in HCM patients with or without obstruction shares some common anatomic features. Additionally, the MV in patients with obstruction has unique characteristics that appear to contribute to LVOT obstruction.