Atrial fibrillation, referred to as atrial fibrillation, is one of the most common clinical arrhythmias. The overall prevalence in the general population is 0.4%, and the prevalence in adults ranges from 0.5% to 0.95%, with a prevalence of 1% in those under 60 years of age. There is a tendency for AF to increase gradually with age, reaching 10% in those over 75 years of age. Episodes of atrial fibrillation (AF) require certain triggers and associated maintenance substrates. Currently, it is believed that abnormal electrical activity in the pulmonary veins is the main trigger of AF, and even the hypothesis of “maintenance pulmonary vein-left atrial foldback of AF” has been proposed [3]. Isolation of the electrical connection between the large vein and the atrium by catheter radiofrequency ablation can terminate the onset of AF and better prevent the recurrence of AF. We have treated 13 patients with paroxysmal atrial fibrillation using three-dimensional electroanatomical markers to guide linear ablation of the left atrial circumflex pulmonary vein vestibule for atrial fibrillation since April 2006 to the present, with a satisfactory postoperative follow-up of 8.0±8.0 months. Deng Jinlong, Department of Cardiovascular Medicine, People’s Hospital of Guangxi Zhuang Autonomous Region 1. DATA AND METHODS 1.1 Clinical data: 13 patients were male, aged 58±8 (35-74) years. All patients were found to have symptomatic paroxysmal atrial fibrillation for more than 1 year, no organic heart disease was found, and antiarrhythmic drug therapy was ineffective. Three of the patients were found to have frequent atrial premature beats, short paroxysmal atrial tachycardia and their triggered atrial fibrillation by dynamic electrocardiography. Patients with hyperthyroidism, left atrial diameter >55 mm, left atrial thrombus, and atrial fibrillation in combination with severe heart disease were excluded. Patients with paroxysmal atrial fibrillation episodes with spontaneous symptoms, more than 3 episodes per week, each lasting more than 1 h, as demonstrated by preoperative ambulatory electrocardiogram. Preoperative anticoagulation therapy was performed for more than 2 weeks, and transthoracic ultrasound was performed to exclude left atrial thrombus. The nature, method and possible complications of the procedure were explained to the patient before the operation, and the consent and signature of the patient’s family were obtained. 1.2 Catheter placement and three-dimensional construction of the left atrium: a 4-pole coronary sinus catheter was inserted through the right subclavian vein puncture to the coronary sinus, respectively; a 4-pole electrode catheter was inserted through the femoral vein and placed in the apical part of the right ventricle; the SL1 Swartz sheath and the septal puncture needle were delivered through the femoral vein puncture, the Swartz sheath was punctured through the septum, and the Navi Star cold saline was delivered along the sheath tube, respectively. A large-tipped catheter with perfusion was delivered into the left atrium. After puncture, 100 u/kg of heparin was injected intravenously and supplemented with 1000 u every hour during the procedure. Pulmonary venography was performed at 45° in the left anterior oblique position and 30° in the right anterior oblique position to observe the opening of each pulmonary vein. Three-dimensional electroanatomical reconstruction of the left atrium was performed using a non-diagnostic navigation system (Carto; Biosense Webster), with a large-ended catheter reaching all parts of the left atrium as far as possible, and data were collected with reference to the local endocardial activation time (LAT) associated with the reference electrogram to construct the left atrium; The site of each pulmonary vein opening was marked by inserting the catheter into each pulmonary vein for 2-4 cm and then dragging it back slowly, and the site of the mitral valve opening was marked by combining the results of pulmonary venography with fluoroscopy and intracardiac electrograms. 1.3 Linear ablation of the left atrial annulus pulmonary vein vestibule: Combined with the three-dimensional reconstruction of the left atrium and X-ray fluoroscopy, a large-headed catheter was used to ablate the large annulus in the ipsilateral pulmonary vein vestibule (1~2 cm outside the pulmonary vein opening). The ablation temperature was set at 43℃, the maximum output energy was 30W, the saline flow was 1020 ml/h during ablation and 120 ml/h during stopping. The ablation time of each target point was greater than 20 s. The local potential amplitude was reduced by more than 50% before moving the target point, and the predetermined ablation line was completed point by point, and, if the patient had no special discomfort, he was transferred to the general ward. Amiodarone 0.2 g (once a day) was given orally for 3 months after the operation, and low molecular heparin 5000 u (twice a day) was applied subcutaneously for 5 consecutive days starting from the night after the operation, followed by oral warfarin anticoagulation for 3 months. During clinical follow-up, 24-h ambulatory ECG, echocardiography and pulmonary vein CT were repeated regularly. 2. Results The mean operation time was 181±41 min, the fluoroscopy time was 60±23 min, and the number of discharges was 120±60 in 13 patients, respectively. There was no stroke or other thromboembolic events. During the postoperative follow-up, patients were regularly asked about their symptoms by telephone, and ambulatory ECG examinations were performed at 2 and 4 months after surgery. During the follow-up period, if the frequency and type of arrhythmia episodes were confirmed by ambulatory ECG as before surgery, they were considered as recurrence. Atrial fibrillation recurred in the second case on the third postoperative day, but was automatically converted to sinus rhythm within a few hours and maintained in sinus rhythm thereafter, while all other patients maintained sinus rhythm; no pulmonary vein stenosis occurred in all patients. Atrial fibrillation tends to increase gradually with age, reaching 10% in people over 75 years of age. In atrial fibrillation, the direction of excitation conduction in the atria is inconsistent, and the frequency is fast and irregular, which causes the atria to lose their effective contraction function. The frequency of atrial excitation in atrial fibrillation is as high as 350-600 beats/min. Although the protection of the atrioventricular node prevents all these excitations from reaching the ventricles, the ventricular rate can still reach 100-160 beats/min, which is not only much faster than normal sinus rhythm, but also absolutely irregular in rhythm. The main hazards of atrial fibrillation are: thrombus formation and embolism: atrial fibrillation when the atria lose their contraction function, blood can easily stagnate in the atria and form thrombus, which can be dislodged with the blood to all parts of the body, leading to cerebral embolism (stroke, hemiplegia), limb artery embolism (serious cases even require amputation) and so on. The annual incidence of stroke is about 1% in patients with atrial fibrillation who are younger than 60 years old without other diseases, and 2% in patients who are 60 to 75 years old or older. If other embolic risk factors are present, the annual incidence of stroke can be as high as 4%. Risk factors for stroke in patients with atrial fibrillation include a history of previous embolism, hypertension, diabetes, coronary artery disease, heart failure, left atrial enlargement, and age over 65 years. Rapid heart rate and irregular rhythm can cause palpitations in patients. Loss of atrial systolic function and prolonged increase in heart rate can lead to heart failure. Increased mortality (twice as high as normal). Treatment of atrial fibrillation: There is no specific drug treatment for atrial fibrillation so far; non-pharmacological treatment (such as atrioventricular node ablation and modification) is not ideal; and surgical maze surgery, although more effective but more invasive, is only suitable for simultaneous direct heart surgery due to other heart diseases. Linear ablation is an alternative to surgical maze surgery, which started to be used in the mid-1990s with a success rate of less than 50%. In 1998, Haissaguerre discovered that most of atrial fibrillation originated in the pulmonary veins, making pulmonary vein ablation a hot topic of research. Currently, pulmonary vein isolation has become the main method of radiofrequency ablation for paroxysmal atrial fibrillation, and it has been proved that the recurrence rate of pulmonary vein isolation method is still high and pulmonary vein stenosis still occurs. Therefore, electrophysiological researchers continue to explore and improve ablation methods.