The incidence of AF is 30% in the preexcitation syndrome population and 3% to 4% in the general population. The indications and efficacy of catheter ablation for preexcitation syndrome are well established, while preexcitation syndrome combined with atrial fibrillation (AF) can lead to hemodynamic disturbances or even ventricular fibrillation, cardiac arrest and death when rapid atrial excitation is transmitted anteriorly, so whether WPW or occult bypass is followed by catheter ablation of AF after bypass ablation ablation has not been clearly defined, and many studies have shown that partial supraventricular tachycardia is the This conclusion is not entirely correct, and it is not clearly defined at what age level and risk factors AF patients do not require intervention? And part of the question was answered recently by Borregaard et al published in Europace. The study, which was designed to evaluate the prognosis and incidence of postoperative AF after prestimulation syndrome, retrospectively analyzed 362 patients with WPW and performed a control analysis with 3610 normal population. The study found no difference in mortality between patients with prestimulation syndrome and the general population, but the incidence of atrial fibrillation after bypass ablation was significantly higher in patients with prestimulation syndrome than in controls (HR: 4.77 and CI: 3.05-7.43). The study also found that the presence of atrial fibrillation before ablation (HR: 4.66 and CI: 2.09-10.41) and age older than 50 years (HR: 9.79 and CI: 4.29-22.36) were independent risk factors for atrial fibrillation after bypass ablation in patients with preexcited syndrome, but were not associated with preoperative bypass anatomical location. Although the incidence of combined atrial fibrillation was found to be higher in patients with right-sided bypass tracts than in patients with left-sided bypass tracts in clinical practice, it was not verified in this study. Second, the KM diagram of the occurrence of postoperative atrial fibrillation in the two groups of patients. Red represents the general population and blue represents patients with pre-excitation syndrome. The study by Dagres et al. showed that patients with bypass combined with paroxysmal AF had a recurrence rate of AF of up to 20% after bypass ablation. In contrast, Derejko et al. showed a recurrence rate of 19% after bypass ablation. Why is the incidence of atrial fibrillation after bypass ablation still so high in preexcited syndrome combined with atrial fibrillation? What are the reasons? The article found a relatively higher incidence of heart failure, hypertension, valvular heart disease, ischemic heart disease, and congenital heart disease in the preexcited syndrome than in the general population, and therefore may be associated with recurrence of atrial fibrillation. However, after the study corrected for the above factors, the incidence of atrial fibrillation was still higher, and the reasons for this need to be further explored. Derejko et al. found that even after successful bypass ablation of preexcited syndrome combined with atrial fibrillation, the role of the pulmonary veins in promoting atrial remodeling continued. The effective pulmonary vein conduction period is significantly shorter, and the delayed pulmonary vein atrial conduction may further trigger atrial fibrillation. Previous studies have also shown that the occurrence of atrial fibrillation after bypass ablation is age-related, especially in patients older than 50 years. In a study published in CMJ in 2013 by Yi-Gang Li in China, two different interventions were studied in 29 cases of preexcited syndrome combined with AF, one group with bypass plus AF ablation (n=19) and the other group with bypass ablation only (n=10). At a mean follow-up of 20 months, the recurrence rate of AF in the bypass plus AF ablation group (2/19, 11%, P < 0.05) was significantly lower than that in the control group (5/10 , 50%). Although there was no difference in the baseline data between the two groups before the procedure, the sample size of this study was too small and the study was not randomized and lacked rigorous follow-up, so the findings of this study need to be further explored. The etiology of atrial fibrillation is complex, and for patients with agitated syndrome combined with atrial fibrillation, both domestic and international guidelines do not provide a specific answer to the question of bypass ablation only or bypass plus atrial fibrillation ablation, nor does the study provide a clear answer, which needs to be considered in a clinical context. In conclusion, it is currently recommended that in patients with paroxysmal AF combined with bypass, patients younger than 50 years of age should undergo bypass ablation for strict follow-up, whereas in patients older than 50 years of age with more risk factors, simultaneous ablation of AF and bypass may be appropriate, taking into account the patient's wishes.