While open heart surgery has much improved the prognosis of tetralogy of Fallot, surgical repair does not usually restore completely normal anatomy. Residual defects include some degree of pulmonary stenosis, pulmonary regurgitation (unavoidable if the pulmonic valve and valve ring need to be widened by patch), and, sometimes, residual ventricular septal defect. In addition, left and right ventricular dysfunction of mild to moderate degree, unrelated to residual lesions, may be observed. Other late complications may arise from conduction disturbances and ventricular arrhythmias. The occurrence of late sudden death is related to such rhythm disturbances, it occurs particularly in patients with ventricular premature beats on routine ECGs and is probably due to ventricular fibrillation. Patients with such premature beats must therefore be treated with antiarrhythmic drugs. In spite of these late complications, the majority of patients lead a normal life and professional integration is usually excellent. Many patients practise sports. Exercise tests late after surgery show mild or moderate decrease in maximal exercise performance if there are residual lesions of significance, and especially when there is more than one such residua (e.g. pulmonic stenosis and regurgitation). Life expectancy should be normal, at least for postoperative patients with minimal residual lesions.