mitral regurgitation

a condition in which the MITRAL VALVE of the HEART is defective and allows BLOOD to leak back from the left VENTRICLE into the left ATRIUM . It is often caused by RHEUMATIC FEVER or can be a congenital defect or the result of MYOCARDIAL INFARCTION . The left ventricle is forced to work harder and enlarges but eventually may be unable to cope, and this can result in left-sided HEART FAILURE . Other symptoms include atrial FIBRILLATION , BREATHLESSNESS and EMBOLISM . Drug treatment and/or surgery to replace the defective valve may be required (mitral prosthesis, see MITRAL STENOSIS ).