Analysis of the risk factors of valvular atrial fibrillation treated with radiofrequency ablation during valve replacement

Purpose To investigate the risk factors of recurrence of atrial fibrillation(AF) after radiofrequency ablation in patients with rheumatic mitral stenosis with persistent atrial fibrillation. Methods From January 2015 to December 2018, patients undergoing radiofrequency ablation of rheumatic mitral stenosis complicated with persistent atrial fibrillation were collected. The patients were divided into sinus rhythm group(Group SR) and atrial fibrillation recurrence group (Group AR). collecting the data of preoperative echocardiography LV,LA,RA,RV,EF and gender, age, whether to combine diabetes, hypertension, etc. logistic regression was used to analyze the risk factors for atrial fibrillation recurrence.

its long-term benefit to patients is recognized [6] . We hope to find the risk factors that affect the failure of the re-law to improve the success rate of surgery. The aim of this study was to find the factors of recurrence of atrial fibrillation after radiofrequency ablation for patients with rheumatic mitral stenosis associated with persistent atrial fibrillation. to more effectively predict the prognosis and screening of patients with atrial fibrillation radiofrequency ablation.

Patients selection:
Patients requiring surgical treatment due to rheumatic moderate-to-severe mitral stenosis with persistent atrial fibrillation in Sichuan Mianyang 404 Hospital from January 2015 to December 2018.
Inclusion criteria:① Moderate to severe rheumatic mitral stenosis with persistent atrial fibrillation (traceable atrial fibrillation greater than 6 months) ② Radiofrequency ablation of atrial fibrillation during replacement of artificial heart valve ③ Cardiac function NYHA class II-III. Exclusion criteria ① Paroxysmal auricular fibrillation ② Patients with cardiac function NYHA-IV ③ No other underlying disease.

Surgery and drug treatment
These were performed by the same treatment team, using COX MAZE IV atrial fibrillation radiofrequency ablation of heart valve replacement and endocardial suture closure for left atrial appendage treatment. after the operation, the amiodarone injection 30-90 mg/h was continuously pumped into the vein for 48 hours, and after 48 hours, it was changed to oral amiodarone 200 mg/day until 3 months after the operation.

Follow-up and Grouping
The 24-hour Holter was reviewed at the outpatient clinic at 3 months, 6 months, and 1 year after the operation. According to the patient's 1-year postoperative period, whether the 24-hour Holter results maintained independently of antiarrhythmic drugs have a continuous room greater than 30 seconds Arrhythmia was divided into group SR and group AR for the endpoint of follow-up.

Collection of medical records
Collect preoperative cardiac color Doppler ultrasound data :LV (mm), LA (mm), RV (mm), RA (mm), EF (%), and gender, age, whether combined with diabetes or hypertension and other data.

Statistical analysis
The data processing was completed by SPSS 18.0 statistical software, and the variable data in accordance with the normal distribution were represented by ± s, using t test for single factor analysis. The classification variables were expressed by count and percentage, and the chi-square test was used to compare the differences between groups. Logistic regression analysis of possible high risk factors in univariate analysis. P <0.05 was considered statistically significant.

General data:
A total of 84 eligible patients were included during the study period, which 69 were successfully followed up, with a follow-up success rate of 82.1%. There were 54 cases (78.3%),53 cases (76.8%) and 53 cases (76.8%) of patients with random atrial arrhythmias without >30 s 24 hr results in 3 months,6 months and 1 year after operation. Patients who were successfully followed up had no pacemaker placement and no deaths. Among them, In the SR group, there were 53 patients, including 20 males and 33 females, 10 patients with hypertension and 7 patients with diabetes. In the AR group, there were 16 patients, including 3 males and 13 females, 3patients with hypertension and 2 patients with diabetes.

Comparison of basic data between the two groups
Data on preoperative gender, age, LA,LV,RA,RV,EF and the incidence of hypertension diabetes etc between the two groups was no statistical difference (P >0.05). (table 1)

Logistic regression analysis
By binary logistic regression analysis, the relationship between LA, LV, RA, RV, EF, gender, age, hypertension, diabetes, and whether cardioversion was successful was performed using the Enter method as the independent variable screening method. The results are as follows (Table 2).No independent risk factors for recurrence of atrial fibrillation after radiofrequency ablation were found. influencing the recurrence of radiofrequency ablation [10] . In particular, many scholars have found that the greater the inner diameter of the left atrium through transcatheter radiofrequency ablation, the greater the possibility of failure of radiofrequency ablation for atrial fibrillation [11][12][13] . However, there are few researches on surgical radiofrequency ablation of rheumatic heart disease with atrial fibrillation. In our clinical work, we will try to follow the results of catheter radiofrequency ablation to avoid radiofrequency atrial fibrillation for patients with a large left atrial diameter, and they will lose the operation to return to sinus rhythm opportunity. This reduces the quality of life after valve replacement. However, through our research, we found that in patients with rheumatic mitral stenosis during persistent atrial fibrillation, radiofrequency ablation during valve replacement, LA, LV, RA, RV, EF, gender, age, diabetes, and hypertension was not an independent risk factor for cardioversion failure. We believe that because the etiology of rheumatic heart disease in combination with persistent atrial fibrillation is diverse [14] , the cause of the failure of the radiofrequency ablation is also the result of multi-cause co-action. In addition to our subjects, there may be factors such as the surgeon's proficiency, the type of atrial fibrillation, the electrical remodeling of the myocardium and structural remodeling. Some studies have found that patients with long course of atrial fibrillation have a significant decrease in their success rate of radiofrequency ablation [11,13,15] . For the reasons for the selection of experimental subjects, we excluded the impact of the course and type of AF on the recurrence of AF. We found that gender may be an important factor affecting the failure of atrial fibrillation in such patients, male (OR 0.192 ,95% CI 0.029-1.279, p 0.088). It seems that men have a higher cardioversion success rate than women, and many catheter radiofrequency ablation procedures have reported similar results [16,17] . Pate and lee ' s study found that the high rate of female radiofrequency ablation regurgitation failure may be associated with higher BMI in women, more ectopic pacing points (non-pv trigers), and higher parasympathetic tension [18,19] . we will continue to improve the relevant research and expand the sample size to further verify the relevant results.

Conclusion
Surgical radiofrequency ablation during heart valve replacement has very good cardioversion effect and safety for valvular persistent atrial fibrillation.LA, LV, RA, RV, EF, gender, age, hypertension, and diabetes are not independent risk factors for recurrence of atrial fibrillation for valvular persistent atrial fibrillation. We recommend that patients with valvular persistent atrial fibrillation can perform radiofrequency ablation at the same time as valve replacement.