What alteration occurs in the aortic valve during diastolic flutter seen in fenestrated aortic valves?

The alteration that occurs in the aortic valve during diastolic flutter seen in fenestrated aortic valves is characterized by a fluttering movement. In cases where the aortic valve has fenestrations, which are small openings or perforations, the valve leaflets can exhibit abnormal motion during diastole. This fluttering occurs as blood flows back toward the left ventricle, causing the valve leaflets to oscillate.

In a normal functioning aortic valve, the leaflets close completely during diastole to prevent backflow, but in the case of fenestrated valves, this backflow can lead to a distinct fluttering instead of a stable closure. This motion is indicative of the compromised structural integrity of the valve due to its fenestration, altering its typical resting position and function during the cardiac cycle.