Original article
Asymmetry of Systolic Anterior Motion of the Mitral Valve in Patients with Hypertrophic Obstructive Cardiomyopathy: A Real-time Three-dimensional Echocardiographic Study

https://doi.org/10.1016/j.echo.2006.04.017Get rights and content

By geometric analysis of real-time 3-dimensional echocardiography performed in 39 patients with hypertrophic obstructive cardiomyopathy and definite systolic anterior motion of the mitral valve, we found that the angle between the mitral annular plane and basal portion of the anterior mitral valve leaflet, and the angle between the basal portion of the anterior leaflet and its tip portion measured in the medial and central anteroposterior planes, were significantly smaller than those in the lateral plane. The distance between the interventricular septum and the anterior mitral valve tip in the medial and central plane was also significantly smaller than that in the lateral plane. The lateral distance between the interventricular septum and the anterior mitral valve tip was the only independent determinant of left ventricular outflow tract pressure gradient by multiple stepwise regression analysis. In conclusion, systolic anterior motion of the mitral valve develops predominantly in the medial side, resulting in laterally located narrow left ventricular outflow tract opening in patients with hypertrophic obstructive cardiomyopathy.

Section snippets

Participants

In all, 39 patients with HOCM (age 43 ± 11 years, 13 women) who had asymmetric septal hypertrophy and underwent RT3DE were enrolled (Table), including 5 patients in whom intraoperative epicardial RT3DE images were obtained for better image quality. Inclusion criteria were: (1) definite SAM; (2) structurally normal mitral valve; and (3) RT3DE images clear enough to analyze. Exclusion criteria were: (1) irregular heart rhythm such as atrial fibrillation; and (2) clinical and echocardiographic

Asymmetry of SAM

Aα measured in the medial and central planes was significantly smaller than that in the lateral plane (45 ± 9, 47 ± 8, and 50 ± 8 degrees, respectively; P < .001) (Figure 3, A). Aα in the medial plane was significantly smaller than that in the central plane (P < .005). Bα in the medial and central plane was also significantly smaller than that in the lateral plane (75 ± 19, 87 ± 16, and 112 ± 16 degrees, respectively; P < .001) (Figure 3, B). Bα in the medial plane was significantly smaller

Discussion

We have demonstrated an asymmetric configuration of SAM in patients with HOCM by the use of RT3DE; SAM develops predominantly in the medial side, resulting in laterally located narrow LVOT opening (Figure 5). More acute-angled SAM was shown in the medial side than lateral side, and larger DS was found in the lateral side than medial side.

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Supported by the Postdoctoral Fellowship Program of Korea Science and Engineering Foundation.

a

Dr Song is now affiliated with Department of Cardiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.

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