Systolic Anterior Motion / SAM
Last modified: 14 September 2023, 11:08:57 AM AEST
Definition / diagnostic criteria1 / 6
- anterior movement of anterior leaflet of mitral valve
- movement into LVOT causing dynamic LVOTO
Classification2 / 6
- Echo grades
- Contact = between mitral leaflet and septum
- Distance = minimum distance between mitral valve and ventricular septum during systole
- 1: No contact, distance = 10 mm
- 2: No contact, distance < 10 mm
- 3: Brief contact < 30% systole time
- 4: Prolonged contact > 30%
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Patient
- HCM = septal hypertrophy
- MR
- Complex dynamic anatomy of LV
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Surgical
- MV repair
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Geometric factors
- eg. Annular undersizing
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Kinetic factors
- eg. Hyperdynamic LV = localised / general
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Structural abnormalities
- eg. redundant MV leaflets, papillary M displacement, bulging septum, small LV
Investigations3 / 6
- Risk assessment = determine clinical significant
- Ameliorate SAM
- administer IVF and vasopressor
- look for reduction in SAM
- Provoke SAM
- administer GTN and rapid ventricular pacing
- look for LVOT
Management4 / 6
- PL = Volume expansion
- HR = rate control
- INO = cease inotropes
- AL = vasoconstrictor
Anaesthetic considerations5 / 6
- Pre-op
- Intra-op
- Prevent tachycardia = Remi
- Maintain afterload = MA
- Post-op