I. Medical history and physical examination Patients who are ready to undergo intracardiac electrophysiological examination and radiofrequency ablation must have a complete medical history, paying particular attention to bleeding disorders, drug allergies, recent diseases, history of previous cardiac catheterization and surgical procedures. In addition to the examination about cardiovascular system, the physical examination should also check whether there are any diseases in other systems such as respiratory, digestive and urinary systems, especially whether the skin at the catheter insertion site is suitable for percutaneous vascular puncture and whether there are thoracic deformities. Fu Rui Bin, Department of Cardiovascular Medicine, Guangzhou General Hospital, Guangzhou Military Region II. Auxiliary examinations 1. ECG examination Routine simultaneous 12-lead ECG examination should be done, preferably with an ECG at the time of attack, to facilitate the determination of the location of the bypass and the type of arrhythmia. Transesophageal cardiac pacing can be considered for patients whose preoperative diagnosis is uncertain. 2. Chest X-ray examination 3. Echocardiography 4. Laboratory examination Mainly includes blood routine, urine and fecal routine, blood clotting time, liver and kidney function, blood electrolytes, and examination of relevant blood infectious diseases (such as hepatitis B triplet, syphilis, hepatitis C antibody, AIDS, etc.). Third, preoperative medication, etc. Discontinue antiarrhythmic drugs for more than 5 half-lives. If there is tachycardia affecting hemodynamics before surgery, try to terminate it with pacing, electrical resuscitation or use short-acting antiarrhythmic drugs. Stress may be given by intraosseous injection of Valium 10mg as appropriate. Preoperative iodine allergy test is required for left atrial ablation. Local skin treatment One day before the operation, the cardiac catheter access site (including bilateral femoral arteries and veins, bilateral subclavian veins and bilateral internal jugular veins) should be washed and skin prepared. If there is local skin infection at the punctured vessel site, it should be cured before the cardiac catheterization is performed. V. Other Preoperative fasting is not necessary, but should not be too full. Children who cannot cooperate should be under general anesthesia. Communicate with the patient and family, introduce the condition and the necessity of interventional consultation and possible complications, and obtain informed consent.