The abnormal bypasses that cause paroxysmal supraventricular tachycardia can grow in a variety of locations around the heart’s annulus, and one, if it happens to be close to the heart’s bundle of Hirschsprung, means in the eyes of the electrophysiologist that it is a dangerous bypass. This is because ablation here would potentially damage the bundle, which is the only pathway for normal electrical conduction in the heart, and if it were to be completely compromised, it would result in a loss of atrial electrical activity, slowing the patient’s heart rate and requiring a pacemaker in severe cases. The traditional method of radiofrequency ablation uses heat to cauterize the abnormal bypass, preserving only the normal conduction pathway of the heart. This method is highly effective, with 96% of bypasses successfully ablated by the thermal energy of radiofrequency. However, it is highly effective and may also injure the surrounding normal tissues due to the heat conduction effect. Therefore, there is a high risk of injury to the normal conduction bundle with RF ablation and cautery for a dangerous bypass such as the Hirschsprung bypass. Electrophysiologists have tried many methods and failed to achieve a good breakthrough, and often choose to abandon the procedure to avoid serious complications. Recently, cryoablation, which has been approved for clinical use in China, offers hope for ablative treatment of this type of bypass. This type of technology has been used in Europe and the United States for many years and has accumulated more experience. In fact, cryoablation has been widely used in the medical field for a long time, such as liquid nitrogen ablation of warts in dermatology. Cryoablation uses a condensing agent (nitrous oxide) to “freeze” the bypass. Nowadays, the latest European guidelines also recommend cryoablation for dangerous bypasses in children. Compared to conventional radiofrequency ablation, cryoablation has the advantage of small damage volume, clear trauma boundaries, stable catheter during ablation, and less likely to be displaced, which makes it more advantageous for dangerous bypasses, especially if signs of normal conduction bundle damage occur during ablation, and normal conduction bundle function can be restored after stopping ablation. Therefore, cryoablation technique is the preferred tool for this type of bypass ablation. Of course, the recurrence rate of cryoablation bypass is slightly higher than that of radiofrequency ablation, but the risk-benefit ratio is self-evident compared to these children who suffer from tachycardia for a long time due to failure to ablate or who are dependent on pacemakers for life due to atrioventricular node injury caused by radiofrequency ablation. As the saying goes, “the green hills are always there and the green water is always flowing”, there is still a chance to operate again if there is a recurrence, but if the AV node is damaged causing a complete AV block, it is not acceptable in children. Now, the introduction of cryoablation will certainly bring a boon to children with dangerous bypasses.