leaf scar. (botany). A mark on a stem, formed by secretion of suberin and a gumlike substance, showing where a leaf has abscised. 1  Facebook. 2  Twitter.
Mitral valve regurgitation means that one of the valves in your heart-the mitral valve-is letting blood leak backward into the heart.Heart valves work like one-way gates, helping blood flow in one direction between heart chambers or in and out of the heart. The mitral valve is on the left side of your heart.It lets blood flow from the upper to the lower heart chamber. See a picture of mitral valve regurgitation.When the mitral valve is damaged-for example, by an infection-it may no longer close tightly.This lets blood leak backward, or regurgitate, into the upper chamber.t lets blood flow from the upper to the lower heart chamber. See a picture of mitral valve regurgitation. When the mitral valve is damaged-for example, by an infection-it may no longer close tightly. This lets blood leak backward, or regurgitate, into the upper chamber.
Most of the time, mitral regurgitation progesses slowly over a period of many years. According to The Cleveland Clinic, the common mitral regurgitation symptoms are: 1  Shortness of breath, especially during exercise or when you are laying still. 2  Fatigue, especially during exercise. 3  Cough, often during the night, when in bed. 4  Heart palpitations, or fluttering heartbeats, atrial fibrillation.