The Study Of Risk Factors Of Recurrent Atrial Fibrillation After Catheter Ablation

Background:Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, and its prevalence has increased during the past few decades. AF is also contributing substantially to cardiac morbidity and mortality. Management of patients with AF requires knowledge of its pattern of presentation, underlying conditions, and decisions about restoration and maintenance of sinus rhythm, control of the ventricular rate, and anti-thrombotic therapy.Catheter ablation such as pulmonary vein isolation (PVI) has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory AF. With continuing advances in techniques and devices of PVI, more patients will be offered this treatment option.However, despite these advances in ablation technique, recurrence of AF following PVI is still frequent during the follow-up. The mechanisms that account for the recurrence are still under research. Uncompleted ablation lines and reconnection with the isolated pulmonary vein activities may contribute to parts of the reasons. Atrial remodeling induced by the "AF begets AF" effect may also play an important role.In order to study these mechanisms mentioned above, we performed two independent Meta-analyses mainly about the two topics below:(1)the association between early recurrent atrial fibrillation (ERAF) and late recurrent atrial fibrillation (LRAF) after catheter ablation; and (2)the association between C-reactive protein (CRP) and recurrence rate of atrial fibrillation following ablation.Part 1:The association between early recurrent atrial fibrillation and late recurrent atrial fibrillation after catheter ablation: a Meta-analysisAims:The main purpose of this part is to explore the association between early recurrent atrial fibrillation and late recurrent atrial fibrillation after catheter ablation. Meanwhile, the clinical characteristics of the patients with early recurrence, late recurrence and "delayed cure" would also be studied.Methods:We searched the online databases of PubMed, Embase, the Cochrane library, and Web of Science for relative literatures published January 2011 or earlier. In addition, manual search with Circulation, JACC, European Heart Journal and Heart Rhythm was also performed. Then, these studies were selected by an including and excluding criteria. The included studies were evaluated according to a quality scoring checklist and the statistical data were extracted. We compared the LRAF rate between the patients with and without ERAF. The clinical characteristics of the patients with ERAF. LRAF and "delayed cure'" would also be analyzed. Heterogeneity test was performed using the Cochrane Q statistic. Subgroup and sensitivity analyses would be performed if significant heterogeneity was found.Results:Of the 260 initially identified studies,14 studies with 4021 patients were finally included. A Meta-analysis of 14 observational studies documented that the risk ratio of LRAF rate between the patients with and without ERAF was 4.59(5%CI 2.94-7.18, P<0.00001). Subgroup analysis revealed that the different definitions of ERAF of the included studies may be a source of heterogeneity. Compared with patients without ERAF, those with ERAF were associated with older age (P=0.0009), longer AF duration (P?.0001), increased left atrium (LA) diameter (P=0.004), and higher prevalence of structure heart disease (SHD) and hypertension (P=0.0004 and P=0.003, respectively). The ratio of paroxysmal atrial fibrillation patients was lower in LRAF group than those without LRAF (P=0.0004). The "delayed cure" patients were associated with younger age (-3.58; 95%CI-5.92--1.24, P=0.003) and smaller LA diameter (-2.38; 95%CI-3.80--0.95, P=0.001) than those with ERAF but absent of "delayed cure". There were no significant differences between the "delayed cure" patients and those without any recurrent AF.Conclusion:The ERAF did not predict LRAF in individual patient. However, the LRAF rate was significantly higher in patients with ERAF than those without. As compared with the patients with ERAF but absent of "delayed cure", the clinical characteristics of patients with "delayed cure" were more similar as those without recurrent AF.Part 2:The association between C-reactive protein and recurrent atrial fibrillation after catheter ablation: a Meta-analysisAims:The objective of this part is to study the association between CRP and AF recurrence after catheter ablationMethods:We searched the online databases of PubMed, Embase, the Cochrane library, and Web of Science for relative literatures published January 2011 or earlier. In addition, manual search with Circulation. JACC. European Heart Journal and Heart Rhythm was also performed. Then, these studies were selected by an including and excluding criteria. The included studies were evaluated according to a quality scoring checklist and the statistical data were extracted. We compared the baseline CRP levels between the patients with AF recurrence and those without. The AF recurrence rates of the patients with high or low CRP levels were also compared. The clinical characteristics of these patients would also be studied. Heterogeneity test was performed using the Cochrane Q statistic. Subgroup and sensitivity analyses would be performed if significant heterogeneity was found.Results:Of the 111 initially identified studies,10 studies with 2021 patients were finally included. A Meta-analysis of 9 included studies documented that the weighted mean difference of baseline CRP levels between the patients with, and those without AF relapse was 0.96 mg/1 (95% CI 0.44 to 1.47; P= 0.0003). Significant heterogeneity was found between these 9 studies (P< 0.0001; 12=77%). Subgroup analysis and sensitivity analysis revealed that repeat ablation procedures and whether excluding patients with SHD might be the sources of heterogeneities. The other meta-analysis with 2 included studies showed that the risk ratio of AF recurrence rates between the patients with high baseline CRP levels and those with low CRP levels was 1.93 (95%CI 1.37 to 2.73; P= 0.0002). The patients with AF recurrence were associated with higher Body Mass Index (P< 0.00001) and increased LA diameter (P< 0.0001) as compared with those without AF recurrence.Conclusion:The baseline CRP levels were associated with AF recurrence rates after successful catheter ablation and increased baseline CRP levels were correlated with higher risk for AF recurrence following ablation.