IVRT ______ indicates severe MR.

IVRT ______ indicates severe MR.

• A. < 60 ms
• B. 60-80 ms
• C. > 100 ms
• D. Not correlated with MR severity.

Answer: (A)

Short isovolemic relaxation time indicates severe MR because regurgitation raises left atrial pressure. When the left atrial pressure is high due to a large MR jet, the LV pressure only has to fall a short distance to become lower than LA pressure, so the mitral valve opens earlier after the aortic valve closes. That makes the interval between aortic valve closure and mitral valve opening very brief, often under about 60 ms. Conversely, if IVRT is prolonged (over about 100 ms), this points more to LV relaxation abnormalities or other diastolic dysfunction rather than MR severity.

Short isovolemic relaxation time indicates severe MR because regurgitation raises left atrial pressure. When the left atrial pressure is high due to a large MR jet, the LV pressure only has to fall a short distance to become lower than LA pressure, so the mitral valve opens earlier after the aortic valve closes. That makes the interval between aortic valve closure and mitral valve opening very brief, often under about 60 ms. Conversely, if IVRT is prolonged (over about 100 ms), this points more to LV relaxation abnormalities or other diastolic dysfunction rather than MR severity.