What exactly is diastolic dysfunction?

Diastolic dysfunctio: Good question....The heart in diastole relaxes and the fibers stretch out as the heart fills. When there is diastolic dysfunction the heart doesn't relax normally and it takes higher pressures to stretch out the fibers to where they can efficiently shorten for systole. This is somewhat oversimplified but hopefully gives you the general idea.....

Diastolic dysf: This occurs when the heart muscle is stiffer than normal and more than a normal amount of pressure is required to fill the heart before it pumps the blood out. If the filling pressure gets too high it results in pulmonary edema and shortness of breath, particularly with exertion. Uncontrolled hypertension is a common cause and can be acute or chronic.