Mitral regurgitation is a leakage of blood that flows backward via the mitral valve during contraction of the left ventricle which results in systolic murmur.
Explanation:
Mitral valve is seen between the left atrium and left ventricle,it prevents the back flow of blood during left ventricular contraction. In case of mitral valve regurgitation or stenosis condition it results in back flow of blood to left atrium it further results in increased blood pressure in left atrium and fluid buildup in lungs and leads to systolic murmur. During cardiac cycle systole occurs when heart contracts and diastole occurs when heart relaxes.