What does MS cause a decrease in?

What does MS cause a decrease in?

• A. LV Outflow
• B. LV Inflow
• C. Cardiac Output
• D. Right Ventricular Systolic Pressure

Answer: (B)

Mitral stenosis directly limits blood flow from the left atrium into the left ventricle during diastole. The narrowed mitral valve reduces the amount of blood that can enter the LV, so LV inflow decreases because filling is impaired. This reduced filling lowers LV preload and can ultimately lower stroke volume and, with exertion, cardiac output. The primary effect of MS is on inflow, not on the outflow tract, which is why LV inflow is the best answer. Right ventricular systolic pressure isn’t decreased by MS (in fact it can rise with resulting pulmonary hypertension), and LV outflow isn’t directly impaired by a mitral valve lesion.

Mitral stenosis directly limits blood flow from the left atrium into the left ventricle during diastole. The narrowed mitral valve reduces the amount of blood that can enter the LV, so LV inflow decreases because filling is impaired. This reduced filling lowers LV preload and can ultimately lower stroke volume and, with exertion, cardiac output. The primary effect of MS is on inflow, not on the outflow tract, which is why LV inflow is the best answer. Right ventricular systolic pressure isn’t decreased by MS (in fact it can rise with resulting pulmonary hypertension), and LV outflow isn’t directly impaired by a mitral valve lesion.