Mitral regurgitation occurs when the mitral valve fails to close completely during contraction, causing some of the blood ejected from the left ventricle during systole to regurgitate back into the left atrium. The mitral valve is the valve between the left atrium and the left ventricle and consists of four parts: the leaflets, the annulus, the tendon cords, and the papillary muscles. Therefore, the mitral valve can fail to close completely due to congenital leaflet malformations or acquired pathologies such as mitral valve prolapse, tendon cable rupture, or papillary muscle ischemia, resulting in partial regurgitation of blood from the left atrium to the left ventricle into the left atrium. Mitral regurgitation can be categorized as mild, moderate, or severe regurgitation depending on the degree of regurgitation. People with mild regurgitation and no symptoms usually do not need to worry too much and follow up regularly as prescribed by the doctor. However, people with moderate or severe regurgitation should consult a doctor in a timely manner and receive standardized treatment under the doctor’s guidance to avoid serious complications such as heart failure.