Paroxysmal supraventricular tachycardia (SVT), referred to as supraventricular tachycardia, is the most common ectopic tachyarrhythmia in the pediatric population and refers to tachycardia with ectopic excitation above the bundle of Hirschsprung. It is mainly caused by a foldback mechanism, followed by increased autoregulation and triggered excitation. It is one of the pediatric emergencies that respond well to drugs and can lead to heart failure if left untreated. It can occur at any age and is prone to recurrent episodes, but initial onset is more common in infancy. Etiology It can occur on the basis of congenital heart disease, pre-excitation syndrome, myocarditis, endocardial elastosis, etc., but most children do not have organic heart disease. Infection is a common trigger, but it can also be triggered by fatigue, stress, hyperventilation, during and after cardiac surgery, and cardiac catheterization. Clinical manifestations Children are often suddenly irritable, pale or blue-gray, cold sweat, weakness, cold skin, increased respiration, weak pulse, often accompanied by a dry cough, and sometimes vomiting. Older children may complain of palpitations, precordial discomfort, dizziness, etc. The heart rate suddenly increases to between 160 and 300 beats per minute during an attack, and an attack can last from several minutes to several days, and the heart rate suddenly slows down and returns to normal when the attack stops. If the attack lasts for more than 24 hours, heart failure will be easily triggered. Ancillary tests 1. Chest X-ray depends on the presence or absence of organic heart disease and heart failure. Fluoroscopy may show a weakened heartbeat. The diagnosis can be confirmed by an electrocardiogram (ECG) during an attack, with abnormal P waves, often smaller than normal, often overlapping with the T waves of the previous heartbeat, making them unrecognizable. Some children may have a pre-excitation syndrome in the interictal period. Treatment 1. Excitation of the vagus nerve to terminate the attack: This method can be used first for those without organic heart disease and no obvious heart failure. Use tongue depressor or fingers to stimulate the pharynx of the child to produce nausea and vomiting, or let the child hold his breath after deep inhalation. 2, the above methods are not effective or immediately effective but soon relapse, the following drug treatment can be considered: (1) Propafenone: significant effect on children with supraventricular tachycardia. (2) Digitalis drugs: suitable for those with severe disease, episodes lasting more than 24 hours, and heart failure. (3) β-blockers: contraindicated in severe AV block, asthma and heart failure. (4) Isoptin: This drug is a selective calcium antagonist. It inhibits the entry of calcium ions into the cells and has a significant therapeutic effect. (5) Amiodarone: for intractable supraventricular tachycardia. 3.Radiofrequency ablation (transcatheterradiofrequencyablation,RFCA) is used as the first choice for the radical treatment of school-age children with frequent attacks that affect normal life and learning.