Systolic anterior motion SAM

Images Genevieve Carbonatto

This gentleman presented septic to our department. He had a history of chronic renal failure requiring dyalisis. BP 88/60, HR 90/min. An ECHO was done in the ED to find a possible cardiac cause, other than hypovolaemia from sepsis, for his hypotension

Watch the clip below. Watch the mitral valve. Then watch the anterior mitral valve leaflet – the one closest to the IVS (interventricular septum). Watch the left ventricle. When the LV contracts, the AMVL (anterior mitral valve leaflet) moves towards the IVS. This is SAM,, systolic anterior motion of the mitral valve and it is causing LVOT (left ventrciular outflow obstruction)

 

end-of-diastole     systole-1

Mitral valve at the end of diastole. MV closed                            As systole begins, the AMV leaflet moves towards the IVS

systole-2  systole-3

The AMV leaflet touches the IVS in early systole , causing brief LVOT obstruction. In mid systole the AMVL returns to the midline

The diagnosis is confirmed by continuous wave Doppler through the LVOT, which shows , in systole, high pressure gradients through the LVOT and a sabre like Doppler spectral trace with late peaking. The pressure gradient is 58.6mmHg. It should be around 4mmHg.

snapshot37

This paradoxical movement of the mitral valve in systole is called SAM and is usually associated with HCM (hypertrophic cardiomyopathy) but has been found to be present in patients who are hypertensive, diabetic ( with LV hypertrophy), and even in asymptomatic patients. It is a dynamic obstruction. It is worse with hypovolaemia, exercise, medications such a nitroglycerine, dobutamine and the Valsalva maoeuvre.

 

 

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