Mucinous tumors are mostly benign tumors that are irregularly shaped and jelly-like. Mucinous tumors are common in the heart and are primary cardiac tumors, found somewhat more frequently in the left atrium. Some mucocele can be found in the right atrium. This mucocele oscillates with the contraction of the heart and the flow of blood, and it may block the mitral valve orifice causing intermittent interruption of blood flow, so it may cause syncope, dyspnea, pulmonary stasis, and other manifestations in patients, and it may also damage the mitral valve annulus. Fragments of atrial mucinous tumors can be shed to various organs of the body with the flow of the heart and blood, leading to vascular embolism in various organs, for example, right atrial mucinous tumor can lead to pulmonary embolism, left atrial mucinous tumor can lead to cerebral embolism, lower limb artery embolism, mesenteric artery embolism, etc. In addition, it may also cause autoimmune system reaction, such as fever, anemia, platelet drop, etc. Atrial mucinous tumors can be detected by cardiac ultrasound and require surgical treatment in cardiac surgery.