Surgical complications 1. Atrioventricular block. If permanent, a pacemaker needs to be implanted. 2.Low cardiac output syndrome. It is the most serious postoperative complication that endangers the patient’s life. 3. Residual shunt and residual valve regurgitation at the atrial and ventricular levels. Small atrial and ventricular residual shunts or small amounts of regurgitant valves usually do not affect the patient, but if the residual shunt is large or if moderate or greater regurgitant valves remain, reoperation is required. 4, pulmonary hypertension crisis. It is a serious postoperative complication that endangers the patient’s life. Postoperative precautions 1.Postoperative cardiotonic, diuretic and vasodilator drugs should be taken for at least 3 months to help restore cardiac function. Early postoperative prevention of respiratory tract infection to prevent serious infection leading to cardiac insufficiency and even life-threatening. 2. Echocardiography should be reviewed 3-6 months after surgery, mainly to observe atrial regurgitation and the presence of residual shunt and left ventricular outflow tract obstruction. Long-term follow-up of the atrioventricular valve, especially the mitral valve, is required in the future.