Mitral tricuspid valve insufficiency can be categorized as chronic, acute, or subacute, and the cause of valve damage can be categorized according to the location of valve damage into leaflet damage, annulus damage, tendon cord damage, and papillary muscle damage, and valve closure insufficiency can occur if damage occurs in any of these locations. 1. Leaflet damage is most commonly caused by rheumatic damage. Chronic inflammation leads to stiffness, shortening, and deformation of the valve, which in turn leads to insufficient closure. 2. Annular damage is caused by enlargement of the left heart due to various reasons (hypertension, hypertrophic cardiomyopathy, etc.), which leads to enlargement of the annulus due to ventricular enlargement, and then leads to relative valve closure insufficiency. 3. Damage to the tendon cords is common in myocardial infarction or infective endocarditis, where rupture of the tendon cords leads to valvular insufficiency. 4. Damage to the papillary muscle is common in acute myocardial infarction, and in severe cases, the papillary muscle ruptures, which can lead to fatal acute valvular insufficiency. Those with mitral tricuspid valve insufficiency need to further improve the examination, assess cardiac function, make a clear diagnosis as soon as possible, and actively treat the disease to avoid progression.