Grading of Systolic Anterior Motion

Systolic anterior motion (SAM) can be graded by echocardiography based on the contact between the mitral valve leaflet and septum during systole.

• Grade I (mild): No contact between the mitral valve leaflet and septum with a minimum separation > 10 mm.
• Grade II (moderate): No contact between the mitral valve leaflet and septum with a minimum separation < 10 mm OR contact between the mitral valve leaflet and septum lasting < 30% of systolic time.
• Grade III (severe) : Contact between the mitral valve leaflet and septum lasting > 30% of systolic time.

References

Gilbert BW, Pollick C, Adelman AG, Wigle ED. Hypertrophic cardiomyopathy: subclassification by m mode echocardiography. Am J Cardiol. 1980 Apr;45(4):861-72.