False-positive M-mode evaluation of MVP occurs when?

False-positive M-mode evaluation of MVP occurs when?

• A. the transducer is placed too low on chest
• B. the transducer is placed too high on chest
• C. the patient is rotated 45 degrees
• D. the left atrial appendage is thickened

Answer: (B)

M-mode MVP assessment relies on the ultrasound beam and M-mode line being through the true plane of the mitral annulus so you measure actual leaflet motion in systole. If the transducer is placed too high on the chest, the imaging plane becomes off-axis relative to the mitral valve. That oblique angle can exaggerate or distort the appearance of leaflet motion, making the leaflets seem to bulge into the left atrium during systole even when they aren’t truly prolapsing. This produces a false-positive MVP on M-mode. Other scenarios shift the view or artifact in different ways and don’t consistently create the same exaggeration of prolapse. Thickening of the left atrial appendage isn’t related to the mitral valve leaflet motion seen on M-mode.

M-mode MVP assessment relies on the ultrasound beam and M-mode line being through the true plane of the mitral annulus so you measure actual leaflet motion in systole. If the transducer is placed too high on the chest, the imaging plane becomes off-axis relative to the mitral valve. That oblique angle can exaggerate or distort the appearance of leaflet motion, making the leaflets seem to bulge into the left atrium during systole even when they aren’t truly prolapsing. This produces a false-positive MVP on M-mode.

Other scenarios shift the view or artifact in different ways and don’t consistently create the same exaggeration of prolapse. Thickening of the left atrial appendage isn’t related to the mitral valve leaflet motion seen on M-mode.