Tetralogy of Fallot (TOF) is the most common form of pediatric cyanotic precursor disease, accounting for about 80% of cases. Its natural prognosis is poor, without surgical treatment, 25% of children die within one year of age, 40% within three years of age, and 70% within 10 years of age, and most of them die from hypoxic episodes or heart failure. From 2002 to 2009, 67 cases of TOF within one year of age were admitted to our department, which are reported as follows: Clinical data General data Among the 67 cases, 41 cases were male and 26 cases were female. Age was 2-12 months, mean 9.06±2.72, and weight was 5-10 kg, mean 6.98±0.96 kg. The diagnosis was confirmed preoperatively by X-ray chest radiograph, electrocardiogram, color ultrasound Doppler, and CT imaging. Preoperative transcutaneous oxygen saturation was 60%-87%. There were 43 cases of TOF alone, 11 cases of TOF combined with patent ductus arteriosus (PDA), 9 cases of TOF combined with atrial septal defect (ASD), 1 case of TOF combined with constriction of the aorta (COA), 2 cases of TOF combined with pulmonary artery atresia (PA), and 1 case of TOF combined with coronary artery anomaly. There were 4 cases of combined thymic agenesis or dysplasia (Digeoge syndrome). Ten of these cases had preoperative hypoxic episodes and were treated with subacute surgery. Intraoperatively, the right ventricular outflow tract was enlarged by a trans-pulmonary annulus patch in 43 cases, and the right ventricular outflow tract was patched alone in 24 cases. 16 cases were kept the patent foramen ovale open. Surgical approach was via oral or transnasal endotracheal intubation and general anesthesia with sedation-aspiration complex. Median sternotomy was performed to enter the chest and extracorporeal circulation was routinely established. The aortic root was perfused with blood-containing cold myocardial protective fluid, and left heart drainage was performed through the patent foramen ovale or ASD. A straight incision is made in the right ventricular outflow tract, and the pulmonary valve and annulus are explored, preserving the integrity of the pulmonary valve as much as possible. The hypertrophic septum and wall bundle muscle were resected, and the ventricular septal defect was repaired with a Dcron patch or its own pericardial slice with 0/5 Prolene continuous suture, and the pulmonary valve annulus was enlarged by a simple right ventricular outflow tract with its own pericardial slice or by a transvalvular enlargement of the pulmonary arteries to the origin of the left pulmonary artery according to pulmonary valve annulus development. Depending on the intraoperative development of the pulmonary artery, it was decided whether to keep the patent foramen ovale open or not. Postoperative ultrafiltration was performed routinely, and a right atrial manometry tube or pacing lead was placed according to the condition. The extracorporeal transit time was 47.2±16 minutes, and the aortic block time was 32.1±14 minutes. Results Of the 67 cases, 5 cases (7.46%) died postoperatively, of which 2 cases were combined with Digeoge’s syndrome, and the parents gave up the treatment because of recurrent postoperative lung infections. The remaining 3 cases died of postoperative hypocardia, and the rest were all cured and discharged from the hospital. There were 12 cases of postoperative low cardiac output, 9 cases were successfully rescued; 1 case of postoperative hemorrhage with secondary thoracotomy for hemostasis; 1 case of sternal infection; 2 cases of pleural effusion; and 6 cases of pulmonary infection. The length of stay in the care unit was 3-12 days, with an average of 4.2 days. Postoperative color ultrasound Doppler examination, ventricular septal defect residual shunt in 2 cases, residual pulmonary artery branching obstruction in 6 cases, moderate pulmonary artery regurgitation in 34 cases, mild pulmonary artery regurgitation in 12 cases. On electrocardiographic follow-up, there were 27 cases of complete right bundle branch block and 23 cases of incomplete right bundle branch block. Follow-up 6 months-5 years, no distant death. Color ultrasound Doppler examination, cardiac function was normal, 2 cases still had increased flow velocity of the left pulmonary artery, moderate pulmonary artery regurgitation in 23 cases, and mild pulmonary artery regurgitation in 22 cases. All children had good growth and development. Discussion TOF is one of the most common pediatric cyanotic coronary artery disease, the natural mortality rate is as high as 25% within one year of age, and most of them die from hypoxic episodes and heart failure. Surgical correction of TOF has been successful for more than 50 years, but controversy still exists in surgical technique and timing of surgery. Theoretically, early correction of TOF can reduce the effects of hypoxia on the development of important organs such as the heart and brain, and early relief of right ventricular outflow tract obstruction can avoid future right ventricular hypertrophy and fibrosis, optimize right ventricular function, and reduce the incidence of postoperative arrhythmias in the long term. Early restoration of normal pulmonary blood flow facilitates normal development of pulmonary vasculature and also avoids the adverse effects of palliative surgery. Many foreign cardiac centers report a perioperative mortality rate of 1.1%-4.5% for one-stage corrective TOF in neonates and infants. Our data showed a mortality rate of 7.46%, but excluding 2 cases of Digeoge syndrome, in which the family abandoned treatment, the actual mortality rate was 4.47%. TOF combined with Digeoge’s syndrome is a special type of children with absent or underdeveloped thymus, immunocompromised, and a history of recurrent upper respiratory tract infections before surgery. Postoperative pulmonary infections are very likely to complicate the postoperative period, resulting in postoperative hypoxemia and difficulty in evacuation. For these children, postoperative aseptic operation should be strengthened, timely detection of respiratory pathogens, application of effective antibiotics to control infection, and application of gammaglobulin to increase immune function. Postoperative hypoventilation is a major factor contributing to death in TOF. To minimize the immediate and long-term effects of surgery on right ventricular function, many scholars have used the right atrial and pulmonary artery routes, a limited right ventricular outflow tract incision to repair ventricular septal defects and to relieve right ventricular outflow tract obstruction.Karl and Hirsch et al. have reported good results. Jonas believed that the right ventricular incision was not the main factor for postoperative low ventricular discharge and long-term arrhythmias, and that intraoperative preservation of the regulatory bundle, avoidance of excessive resection of the right ventricular myocardial bundle, maintenance of good tricuspid valve function, complete relief of the right ventricular outflow tract obstruction, and protection of the conus arteriosus of the right ventricular outflow tract were the fundamental factors. In our experience, there is no difficulty in repairing ventricular septal defects via the tricuspid valve, but it is often difficult to unblock the right ventricular outflow tract, and ChristosAlexiou et al. reported that the rate of reoperation due to right ventricular outflow tract obstruction was significantly higher after transatrial TOF than that of right ventricular TOF, and there was no significant difference in the long-term survival rate, the incidence of arrhythmia, and cardiac function status between these two routes, so that it is believed that early relief of right ventricular outflow tract obstruction is essential. It is believed that early relief of right ventricular outflow tract obstruction to avoid myocardial fibrosis is more beneficial than right ventriculotomy. In fact, some children with TOF may have fewer hypertrophic muscle bundles in the right ventricular outflow tract and mainly show hypoplasia of the right ventricular outflow tract, which can only be relieved by patch enlargement of the outflow tract. Residual right ventricular outflow tract obstruction and pulmonary valve regurgitation after corrective surgery for TOF are the main causes of near- and long-term outcome and reoperation interventions. Intraoperative transannular patching is mainly based on the development of the pulmonary annulus, and our principle is to keep the pulmonary valve as intact as possible while ensuring no obstruction.Bacha et al. reported that the main reason for postoperative reoperation intervention was recurrence of right ventricular outflow tract obstruction.3 The main reason for postoperative reoperation was the recurrence of right ventricular outflow tract obstruction. Studies from several other centers have shown that patients with postoperative right ventricular outflow tract obstruction have the worst long-term outcome. In our follow-up, we found that some small infants had faster postoperative pulmonary artery branch flow velocities, whereas after 1-2 years, pulmonary artery branch flow velocities were close to normal, possibly because of the promotion of pulmonary vascularization after the early restoration of normal pulmonary blood flow. Pulmonary regurgitation is unavoidable after TOF corrective surgery, and it is especially pronounced in patients who have undergone transannular patching. In order to reduce the impact of pulmonary regurgitation on cardiac function, many scholars have used right ventricular outflow tract reconstruction with a single-valve patch, which is effective in the near term, but the single-valve will soon lose its function in the long term. The tricuspid valve must be carefully examined during surgery to ensure normal tricuspid valve function in those with transannular patches. In the postoperative follow-up of our cases, the pulmonary regurgitation was below moderate and the cardiac function was normal, which may be related to our short follow-up time. There are reports of severe pulmonary regurgitation in the long term requiring valve implantation, and there are also advocates of early postoperative pulmonary valve implantation to avoid further deterioration of right ventricular function. Currently, progressive right ventricular dilatation, right heart failure, reduced activity tolerance, and arrhythmias after TOF are considered indications for pulmonary valve implantation. We found that small infants had a higher incidence of low cardiac output and pleural effusion after TOF and a longer stay in the care unit than older children. Therefore, close postoperative monitoring and timely management of related complications should be performed to ensure smooth recovery of the child. In conclusion, the effect of one-stage surgical correction of TOF in infancy is satisfactory, and early correction can reduce the harmful effects of hypoxia and right ventricular outflow tract obstruction on cardiac function, promote the normal development of the pulmonary vasculature, which is also conducive to the normal development of other important organs, and reduce the incidence of complications such as arrhythmia in the long term.