The Study Of Risk Factors For Recurrence Of Atrial Fibrillation After Radiofrequency Catheter Ablation

Part 1:The effect of left atrium size on atrial fibrillation recurrence after radiofrequency catheter ablationBackgroud and aims:Atrial fibrillation(AF)is the most common arrhythmia occurring in the general population,which is associated with an increased risk of stroke,cardiovascular disease,and death.With the rapid development of treatment,radiofrequency catheter ablation(RFCA)has gradually become a cornerstone in the treatment of atrial fibrillation.The recurrence rate of atrial fibrillation after RFCA is still high,which has become a major problem that needs to be solved in our clinical work.Previous studies have found that the left atrium anteroposterior dimension(LAD)is significantly related to postoperative recurrence.The larger the LAD,the higher the prevalence of AF recurrence.However,does the relationship between LAD and AF recurrence have to be linear?In our large clinical practice,we have also found that patients with a smaller left atrium(especially LAD<3.0cm)might also have an increased risk of AF recurrence after catheter ablation.Therefore,the main aim of this study was to verify whether LAD is associated with recurrence of atrial fibrillation after radiofrequency ablation,analyze the different baseline characteristics between the patients with diffirent atrium size and try to clarify the relationship between smaller LA size and the recurrence of AF,in order to provide sufficient evidence-based evidence for the clinical treatment strategy of atrial fibrillation.Methods:This prospective observational study enrolled 542 consecutive patients with nonvalvular atrial fibrillation who underwent RFCA at the First Affiliated Hospital of Zhejiang University School of Medicine between January 2015 and July 2017.19 patients were lost to follow-up and 2 patients died.521 consecutive patients were finally identified for the study cohort and analysis.The clinical characteristics,laboratory examinations,cardiac ultrasonography and other baseline data were collected for all patients before RFCA.The follow-up period was at least 1 year and patients were followed by trained physicians in the dedicated arrhythmia outpatient clinic.The clinical baseline characteristics were compared between patients with different left atrium sizes and the independent risk factors for recurrence of atrial fibrillation after ablation were screened by multivariate Cox proportional hazard models.Results:Compared with the no recurrence group,patients with recurrence after ablation had a higher proportion of persistent atrial fibrillation(22.7%vs.12.0%;P=0.003),larger left atrium diameter(4.1±0.76 vs.3.9±0.53 cm;P<0.001)and higher left atrium volume calculated using the ellipsoid model/body surface area(LAVe/BSA,LAVI)(34.81±13.88vs.30.79±9.75 m L/m~2;P<0.001).The patients were divided into 7 groups on the basis of LAD in 0.4-cm increments in the following manner:LAD≤3 cm,3.0<LAD≤3.4 cm,3.4<LAD≤3.8 cm,3.8<LAD≤4.2 cm,4.2<LAD≤4.6 cm,4.6<LAD≤5.0 cm;and LAD>5.0 cm.With regard to the LAD subgroups,the results showed that with the increase of the left atrial diameter,the left ventricular diameter(P=0.002)and the left atrial volume index(P<0.001)increased,and the left ventricular ejection fraction decreased(P<0.001)accordingly.In addition,there was a positive linear relationship between left atrium size and age(P=0.001)and BMI(P<0.001).Left atrial enlargement was also significantly associated with hypertension(P=0.033)and cardiovascular disease(P=0.012),and may increase the risk of diabetes,but there was no statistically significant difference(P=0.070).On multivariate analysis,AF type[Hazard ratio(HR)0.64;95%CI:0.42–0.99,P=0.042],LAD(HR 1.52;95%CI:1.12–2.05,P=0.007),and LAVI(HR 1.19;95%CI:1.09–1.30,P<0.001)were independent predictors of AF recurrence.Compared with the 3.4–3.8-cm group,the adjusted HR were 3.88(95%CI:2.02–7.46,P<0.001),1.03(95%CI:0.50–2.12,P=0.939),0.96(95%CI:0.52–1.77,P=0.901),1.36(95%CI:0.72–2.57,P=0.347),3.04(95%CI:1.67–5.53,P<0.001),and 4.07(95%CI:1.93–8.60,P<0.001),respectively.P<0.001).LAD 3.0–4.6 cm was associated with the lowest AF recurrence.When LAD was<3.0 cm or>4.6 cm,the prevalence of AF recurrence increased progressively,and followed a U-shaped curve.Restricted cubic spline analysis confirmed a non-linear association between LAD and AF recurrence.The relationship between LAVe/BSA and AF recurrence also showed a similar U-shaped trend.Conclusion:LAD was significantly correlated with the structure and function of the left ventricle,age,BMI,hypertension and other accompanied cardiovascular diseases.AF type,LAD and LAVe/BSA were independent predictors of atrial fibrillation recurrence after radiofrequency ablation.Patients with LAD of 3.4-3.8 cm and LAVe/BSA of 25-30m L/m~2 had the lowest recurrence rate.The association of LA size and AF recurrence after RFCA is represented by a U-shaped curve.Part 2: The value of SAMe-TT2R2 score in predicting atrial fibrillation recurrence for patients on warfarin after radiofrequency catheter ablation —— compared with CHA2DS2-VASc scoreBackgroud and aims:Atrial fibrillation(AF)is one of the most common arrhythmias in clinic.With the development of treatment techniques in recent years,radiofrequency catheter ablation(RFCA)has gradually become one of the main methods for the treatment of atrial fibrillation.Oral anticoagulation(OAC)is central to the prevention of ischemic vascular events in patients with atrial fibrillation,and patients worldwide are treated with vitamin K antagonists [(VKAs)e.g.warfarin] for thrombosis and cardioembolic stroke prevention.New oral anticoagulants(NOACs)are often been preferred over warfarin because of the efficacy and safety profiles.However,NOACs are expensive and medication compliance is poor.Thus,warfarin remains an important anticoagulant choice in China and other developing countries.Warfarin-treated patients tend to be economically disadvantaged and have the poorer clinical conditions,thus we should be more concerned with optimizing their care.In clinical practice,we found that the CHA2DS2-VASc and SAMeTT2R2 scores were associated with the risk of AF recurrence after RFCA in warfarintreated patients.Previous studies have found that the CHA2DS2-VASc score was an independent predictor of AF recurrence after RFCA.However,there is a paucity of data regarding the SAMe-TT2R2 score as predictor of outcomes among patients with nonvalvular atrial fibrillation on vitamin K antagonists after RFCA.Therefore,the objective of this study was to explore the predictive value of the SAMe-TT2R2 scoring system in AF recurrence after RFCA in warfarin-treated patients,and compared it with the CHA2DS2-VASc scoring system,in order to provide sufficient evidence-based evidence for the clinical treatment strategy for warfarin-treated patients.Methods:This study enrolled 304 consecutive patients with nonvalvular atrial fibrillation who underwent RFCA at the First Affiliated Hospital of Zhejiang University School of Medicine between January 2015 and October 2017.Warfarin was continued for at least 3 months after RFCA.The clinical characteristics,laboratory examinations,cardiac ultrasonography,CHA2DS2-VASc and SAMe-TT2R2 scores,and other baseline data were collected for all patients before RFCA.The follow-up period was at least 1 year and patients were followed by trained physicians in the dedicated arrhythmia outpatient clinic.We explored the predictive value of the CHA2DS2-VASc and SAMe-TT2R2 scoring systems in AF recurrence after RFCA in warfarin-treated patients,and compared the predictive performance of these two scoring systems.Results:Compared with the no recurrence group,patients with recurrence after ablation had a larger left atrium diameter(4.1±0.7 vs.3.9±0.5 cm;P=0.003)and higher CHA2DS2-VASc [2(1-2)vs.1(1-2);P=0.002] and SAMe-TT2R2 [5(4-5)vs.4(4-5);P<0.001] scores.Patients with persistent atrial fibrillation(26.0% vs.12.3%;P=0.005),heart failure(27.3% vs.3.1%;P<0.001),and current smoking status(32.5% vs.14.1%;P<0.001)had a higher risk of recurrence.The atrial fibrillation recurrence rates progressively increased and matched parallel increases in the CHA2DS2-VASc/ SAMe-TT2R2 scores.Cutoff point analysis showed that a CHA2DS2-VASc score at least 3 had the highest predictive value for atrial fibrillation recurrence [areas under the curve(AUC)= 0.612,95% confidence interval(CI)0.537–0.687].Similarly,there was a trend towards higher recurrence rates with higher SAMe-TT2R2 scores.Cutoff point analysis showed that a SAMe-TT2R2 score at least 5 had the highest predictive value for atrial fibrillation recurrence(AUC = 0.642,95% CI 0.575–0.708).Delong’s test showed that there was no significant difference between these two scoring systems in predicting AF recurrence after ablation(Z statistic=0.588,P=0.278).On multivariate analysis,persistent atrial fibrillation [Hazard ratio(HR): 1.98;95% CI:1.16-3.39,P=0.012],an enlarged left atrium(HR: 1.54;95% CI: 1.06-2.25,P=0.024),heart failure(HR: 4.57;95% CI:2.67-7.83,P<0.001),current smoking status(HR: 2.39;95% CI:1.35-4.24,P=0.003),CHA2DS2-VASc score at least 3(HR: 1.99;95% CI:1.19-3.33,P=0.008)and SAMe-TT2R2 score at least 5(HR: 2.09;95% CI:1.34-3.28,P=0.001)had a significant association with atrial fibrillation recurrence.Conclusion:Persistent AF,enlarged left atrium,heart failure and current smoking status were independent predictors of atrial fibrillation recurrence after radiofrequency ablation.The CHA2DS2-VASc and SAMe-TT2R2 score systems were associated with atrial fibrillation recurrences in patients on VKAs after RFCA.Cutoff points of at least 3 and at least 5 for the CHA2DS2-VASc and SAMe-TT2R2 scores,respectively,had the highest predictive value for atrial fibrillation recurrence.There was no significant difference between these two scoring systems in predicting AF recurrence after ablation.