In mitral stenosis, the mitral valve closes later because LV pressure equals what?

In mitral stenosis, the mitral valve closes later because LV pressure equals what?

• A. Elevated left atrial pressure
• B. Elevated right atrial pressure
• C. Elevated aortic pressure
• D. Normal LV diastolic pressure

Answer: (A)

In mitral stenosis, the left atrial pressure becomes elevated because the narrowed mitral opening resists blood flow from the atrium into the ventricle. The mitral valve closes when the left ventricle’s pressure rises above the left atrial pressure. Because the atrial pressure is so high, the ventricle must generate a higher pressure to match it, so the moment LV pressure equals LA pressure occurs later in the cardiac cycle. That matching of pressures is what triggers the valve to close, hence the late closure. Elevated left atrial pressure is the key factor driving this timing.

In mitral stenosis, the left atrial pressure becomes elevated because the narrowed mitral opening resists blood flow from the atrium into the ventricle. The mitral valve closes when the left ventricle’s pressure rises above the left atrial pressure. Because the atrial pressure is so high, the ventricle must generate a higher pressure to match it, so the moment LV pressure equals LA pressure occurs later in the cardiac cycle. That matching of pressures is what triggers the valve to close, hence the late closure. Elevated left atrial pressure is the key factor driving this timing.