An ECG is a mandatory part of the usual physical examination and is also important for people without previous heart disease. ECG as a basic test can provide a lot of information about the heart. Some time ago there was a young patient who was very nervous about the detection of pre-excitation syndrome in his physical examination, so he called for advice on how to treat it. So, are there any symptoms for the discovery of pre-excitation syndrome and should it be treated surgically? This article will briefly introduce some scientific knowledge of preexcitation syndrome. I. What is preexcitation syndrome? Ventricular preexcitation is an abnormal phenomenon of atrioventricular conduction, which refers to the downward transmission of impulses from the sinus node through the bypass tract to excite the ventricles in advance, causing some ventricular muscles to be excited in advance. The preexcitation syndrome is often combined with episodes of tachycardia, causing palpitations, weakness and other uncomfortable symptoms due to the preexcitation of the bypass. It is a relatively rare arrhythmia in clinical practice, and the diagnosis relies mainly on the electrocardiogram. Electrocardiographically detectable overt preexcitation accounts for 0.15% to 0.25% of the total population, but the prevalence rises to 0.55% in first-degree relatives of patients with typical preexcitation syndrome, and the family history of preexcitation is associated with patients having multiple bypasses. Second, does preexcitation syndrome require treatment? Preexcitation alone does not require specific treatment if it is not combined with an episode of supraventricular tachycardia. However, many patients with preexcitation syndrome are prone to complications of supraventricular tachycardia and require regular pharmacological or surgical treatment. In addition, if a patient with preexcitation syndrome is complicated by atrial fibrillation or atrial flutter, it is advisable to use synchronized direct current resuscitation to convert to normal rhythm as soon as possible, often because of the fast ventricular rate and the resulting hemodynamic instability. This type of arrhythmia is a more dangerous type, as the rapid ventricular rate can easily lead to a drop in blood pressure and even ventricular tachycardia and ventricular fibrillation, which can be life-threatening. Drugs such as procainamide, propafenone and amiodarone are commonly used to slow down the conduction of the bypass, which can slow down the ventricular rate or convert atrial fibrillation and atrial flutter to sinus rhythm. To avoid recurrence of AF combined with pre-excitation syndrome in such patients, complete surgical treatment should be performed. For those who are intended to participate in high-risk occupations, aggressive surgical radical elimination bypass therapy should be performed if preexcitation syndrome is detected. Third, what are the specific treatment means? First of all, let’s talk about drug treatment. The main drugs commonly used in preexcitation syndrome and tachycardia are: propafenone, procainamide, amiodarone and other drug treatments, which can be applied to inhibit bypass conduction because the above drugs can slow down bypass conduction. The drugs such as digitalis, verapamil, metoprolol, adenosine, etc. mainly block AV node conduction and are therefore contraindicated: if the above drugs are ineffective or if the arrhythmia is exacerbated or the disease develops critically and is hemodynamically unstable, synchronized electrical resuscitation should be performed immediately. The majority of patients are successfully resuscitated immediately and without complications. Transcatheter radiofrequency ablation for preexcitation syndrome combined with tachyarrhythmias has been very successful, with a success rate of over 90%. The main indications for transcatheter radiofrequency ablation of preexcitation syndrome include: preexcitation syndrome with symptomatic persistent atrial fibrillation tachycardia, where drug therapy is ineffective or intolerable, or where the patient is unwilling to take long-term antiarrhythmic drugs to control the above arrhythmia; atrial fibrillation or other rapid atrial arrhythmias with bypass antegrade transmission causing rapid ventricular rate, where drug therapy is ineffective or intolerable, or where the patient is unwilling to take long-term antiarrhythmic drugs. Patients with atrial fibrillation or other rapid atrial arrhythmias with bypass antegrade transmission with rapid ventricular rate who are not tolerated by drug therapy or who are unwilling to take anti-arrhythmic drugs for a long time. How to prevent pre-excitation syndrome? For the prevention of preexcitation syndrome, the main focus is to prevent episodes of supraventricular tachycardia. In order to effectively prevent the recurrence of tachycardia, drugs can be used to inhibit both the forward and reverse conduction of the refractory pathway, and the choice of drugs can be based on clinical experience or on drugs determined to be effective by cardiac electrophysiological examination. This ensures the best recurrence prevention effect.