Project description:Common single nucleotide polymorphisms at chromosome 4q25 (rs2200733, rs10033464) are associated with both lone and typical atrial fibrillation (AF). Risk alleles at 4q25 have recently been shown to predict recurrence of AF after ablation in a population of predominately lone AF, but lone AF represents only 5%-30% of AF cases.To test the hypothesis that 4q25 AF risk alleles can predict response to AF ablation in the majority of AF cases.Patients enrolled in the Vanderbilt AF Registry underwent 378 catheter-based AF ablations (median age 60 years; 71% men; 89% typical AF) between 2004 and 2011. The primary end point was time to recurrence of any nonsinus atrial tachyarrhythmia (atrial tachycardia, atrial flutter, or AF).Two-hundred atrial tachycardia, atrial flutter, or AF recurrences (53%) were observed. In multivariable analysis, the rs2200733 risk allele predicted a 24% shorter recurrence-free time (survival time ratio 0.76; 95% confidence interval [CI] 0.6-0.95; P = .016) compared with wild type. The heterozygous haplotype demonstrated a 21% shorter recurrence-free time (survival time ratio 0.79; 95% CI 0.62-0.99) and the homozygous risk allele carriers a 39% shorter recurrence-free time (survival time ratio 0.61; 95% CI 0.37-1.0; P = .037).Risk alleles at the 4q25 loci predict impaired clinical response to AF ablation in a population of patients with predominately typical AF. Our findings suggest that the rs2200733 polymorphism may hold promise as an objectively measured patient characteristic that can be used as a clinical tool for selecting patients for AF ablation.
Project description:Genetic variants on chromosome 4q25 are associated with atrial fibrillation (AF). We sought to determine whether there is more than 1 susceptibility signal at this locus.Thirty-four haplotype-tagging single-nucleotide polymorphisms (SNPs) at the 4q25 locus were genotyped in 790 case and 1177 control subjects from Massachusetts General Hospital and tested for association with AF. We replicated SNPs associated with AF after adjustment for the most significantly associated SNP in 5066 case and 30 661 referent subjects from the German Competence Network for Atrial Fibrillation, Atherosclerosis Risk In Communities Study, Cleveland Clinic Lone AF Study, Cardiovascular Health Study, and Rotterdam Study. All subjects were of European ancestry. A multimarker risk score composed of SNPs that tagged distinct AF susceptibility signals was constructed and tested for association with AF, and all results were subjected to meta-analysis. The previously reported SNP, rs2200733, was most significantly associated with AF (minor allele odds ratio 1.80, 95% confidence interval 1.50 to 2.15, P=1.2 x 10(-20)) in the discovery sample. Adjustment for rs2200733 genotype revealed 2 additional susceptibility signals marked by rs17570669 and rs3853445. A graded risk of AF was observed with an increasing number of AF risk alleles at SNPs that tagged these 3 susceptibility signals.We identified 2 novel AF susceptibility signals on chromosome 4q25. Consideration of multiple susceptibility signals at chromosome 4q25 identifies individuals with an increased risk of AF and may localize regulatory elements at the locus with biological relevance in the pathogenesis of AF.
Project description:Background:Recent studies suggested that variants on chromosome loci 4q25, 1q21, and 16q22 were associated with atrial fibrillation recurrence after catheter ablation. In this study, we performed a systematic review and meta-analysis to explore the association between variants on chromosome loci 4q25, 1q21, and 16q22 and atrial fibrillation recurrence after catheter ablation. Methods:We comprehensively searched the databases of MEDLINE and EMBASE from inception to January 2017. Included studies were published prospective or retrospective cohort and case control studies that compared the risk of atrial fibrillation recurrence after catheter ablation in AF patients with chromosome 4q25, 1q21, and 16q22 variants versus no variants. Single-nucleotide polymorphism rs1906617, rs2106261, rs7193343, rs2200733, rs10033464, rs13376333, and rs6843082 were included in this analysis. Data from each study were combined using the random-effects, generic inverse variance method of DerSimonian and Laird to calculate the risk ratios and 95% confidence intervals. Results:Seven studies from January 2010 to June 2017 involving 3,322 atrial fibrillation patients were included in this meta-analysis. According to the pooled analysis, there was a strong independent association between chromosome 4q25 variant (rs2200733) and the risk of atrial fibrillation recurrence after catheter ablation (risk ratio 1.45 [95% confidence interval 1.15-1.83], P = 0.002). No association was found in other variants. Conclusion:Our meta-analysis demonstrates a statistically significant increased risk of atrial fibrillation recurrence after catheter ablation in 4q25 variant (only in rs2200733) but not in 1q21 or 16q22 variants.
Project description:To test polymorphisms rs2200733 (chromosome 4q25) and rs2106261 (ZFHX3) were associated with AF recurrence after catheter ablation in a Chinese Han cohort. A total of 235 AF patients who underwent catheter ablation were recruited consecutively. Two polymorphisms were amplified by polymerase chain reaction and genotyped using high resolution melting analysis. Primary endpoints for AF recurrence were defined as the time to the first recurrence of atrial tachycardia/flutter/fibrillation (AT/AF). AT/AF recurrence was observed in 76 patients (35%). Allelic analysis demonstrated that rs2200733 was strongly associated with AF recurrence after ablation (P = 0.011) and the minor allele T increased the risk for recurrence (OR = 1.715). Diameters of the right atrium as well as the left and right superior pulmonary veins (PVs) were associated with rs2200733 in different genetic models (P = 0.040, 0.047 and 0.028, respectively). No significant association was detected between rs2106261 and AT/AF recurrence after ablation or atrial/PV diameters in any models. On multivariate Cox regression analysis, only rs2200733 was an independent factor of AF recurrence after ablation (HR = 0.532, P = 0.022). In Chinese Han population, rs2200733 but not rs2106261 is associated with AT/AF recurrence after ablation. The patients with genotype TT have larger size of right atrium and superior PVs than those of CC genotype. The findings suggest that rs2200733 may play a key role in regulating proper development and differentiation of atria/PVs.
Project description:BackgroundPrevious studies have suggested PITX2, KCNN3 and ZFHX3 as atrial fibrillation (AF) susceptibility genes. Single common genetic polymorphisms of those genes have been linked with AF phenotypes and rhythm outcome of AF catheter ablation although their mechanisms remain elusive. New gene-based association tests may help clarifying genotype-phenotype correlations. Therefore, we hypothesized that PITX2, KCNN3 and ZFHX3 associate with left atrial enlargement and persistent AF and subsequently with ablation outcome.Methods and resultsSamples from 660 patients with paroxysmal (n = 370) or persistent AF (n = 290) undergoing AF catheter ablation were genotyped for ~1,000,000 SNPs. Gene-based association was investigated using two different gene-based association tests (VEGAS, minSNP). Among the three candidate genes, only ZFHX3 associated with left atrial dilatation and AF recurrence after catheter ablation.ConclusionThis study suggests a contribution of ZFHX3 to AF remodeling and response to therapy. Future and larger studies are necessary to replicate and apply these findings with an emphasis on designing AF pathophysiology-based multi-locus risk scores.
Project description:BACKGROUND:Combined 'hybrid' thoracoscopic and percutaneous atrial fibrillation (AF) ablation is a strategy used to treat AF in patients with therapy-resistant symptomatic AF. We aimed to study efficacy and safety of single-stage hybrid AF ablation in patients with symptomatic persistent AF, or paroxysmal AF with failed endocardial ablation, and assess determinants of success and quality of life. METHODS:We included consecutive patients undergoing single-stage hybrid AF ablation. First, we performed epicardial ablation, via thoracoscopic access, to isolate the pulmonary veins and superior caval vein and to create a posterior left atrial box. Thereafter, isolation was assessed endocardially and complementary endocardial ablation was performed, followed by cavotricuspid isthmus ablation. Efficacy was assessed by 12-lead electrocardiography and 72-hour Holter monitoring after 3, 6 and 12 months. Recurrence was defined as AF/atrial flutter/tachycardia recorded by electrocardiography or Holter monitoring lasting >30?s during 1?year follow-up. RESULTS:Fifty patients were included, 57?±?9 years, 38 (76%) men, 5 (10%) paroxysmal, 34 (68%) persistent and 11 (22%) long-standing persistent AF. At 1?year 38 (76%) maintained sinus rhythm off antiarrhythmic drugs. Majority of recurrences were atrial flutter (9/12 patients). Success was associated with type of AF (p?=?0.039). Patients with paroxysmal AF had highest success, patients with longstanding persistent AF had lowest success. Seven (14%) patients had procedure-related complications. Quality of life improved after ablation in patients who maintained sinus rhythm. CONCLUSION:Success of single-stage hybrid AF ablation was 76% off antiarrhythmic drugs, being associated with type of AF. Quality of life improved significantly, Procedure-related complications occurred in 14%.
Project description:AF is a heterogeneous rhythm disorder that is related to a wide spectrum of etiologies and has broad clinical presentations. Mechanisms underlying AF are complex and remain incompletely understood despite extensive research. They associate interactions between triggers, substrate and modulators including ionic and anatomic remodeling, genetic predisposition and neuro-humoral contributors. The pulmonary veins play a key role in the pathogenesis of AF and their isolation is associated to high rates of AF freedom in patients with paroxysmal AF. However, ablation of persistent AF remains less effective, mainly limited by the difficulty to identify the sources sustaining AF. Many theories were advanced to explain the perpetuation of this form of AF, ranging from a single localized focal and reentrant source to diffuse bi-atrial multiple wavelets. Translating these mechanisms to the clinical practice remains challenging and limited by the spatio-temporal resolution of the mapping techniques. AF is driven by focal or reentrant activities that are initially clustered in a relatively limited atrial surface then disseminate everywhere in both atria. Evidence for structural remodeling, mainly represented by atrial fibrosis suggests that reentrant activities using anatomical substrate are the key mechanism sustaining AF. These reentries can be endocardial, epicardial, and intramural which makes them less accessible for mapping and for ablation. Subsequently, early interventions before irreversible remodeling are of major importance. Circumferential pulmonary vein isolation remains the cornerstone of the treatment of AF, regardless of the AF form and of the AF duration. No ablation strategy consistently demonstrated superiority to pulmonary vein isolation in preventing long term recurrences of atrial arrhythmias. Further research that allows accurate identification of the mechanisms underlying AF and efficient ablation should improve the results of PsAF ablation.
Project description:Background and objectivesThe association of susceptibility loci for atrial fibrillation (AF) with AF recurrence after ablation has been reported, although with controversial results. In this prospective cohort analysis, we aimed to investigate whether a genetic risk score (GRS) can predict the rhythm outcomes after catheter ablation of AF.MethodsWe determined the association between 20 AF-susceptible single nucleotide polymorphisms (SNPs) and AF recurrence after catheter ablation in 746 patients (74% males; age, 59±11 years; 56% paroxysmal AF). A GRS was calculated by summing the unweighted numbers of risk alleles of selected SNPs. A Cox proportional hazard model was used to identify the association between the GRS and risk of AF recurrence after catheter ablation.ResultsAF recurrences after catheter ablation occurred in 168 (22.5%) subjects with a median follow-up of 23 months. The GRS was calculated using 5 SNPs (rs1448818, rs2200733, rs6843082, rs6838973 at chromosome 4q25 [PITX2] and rs2106261 at chromosome 16q22 [ZFHX3]), which showed modest associations with AF recurrence. The GRS was significantly associated with AF recurrence (hazard ratio [HR] per each score, 1.13; 95% confidence interval [CI], 1.03-1.24). Patients with intermediate (GRS 4-6) and high risks (GRS 7-10) showed HRs of 2.00 (95% CI, 0.99-4.04) and 2.66 (95% CI, 1.32-5.37), respectively, compared to patients with low risk (GRS 0-3).ConclusionsOur novel GRS using 5 AF-susceptible SNPs was strongly associated with AF recurrence after catheter ablation in Korean population, beyond clinical risk factors. Further efforts are warranted to construct a generalizable, robust genetic prediction model which can guide the optimal treatment strategies.
Project description:Our study aims to elucidate the role of lncRNA-mRNA regulatory networks in AF recurrence after catheter ablation. We performed RNA sequencing to profile the transcriptomes of 5 samples from atrial fibrillation recurrence and 5 samples from sinus rhythm maintenance. 96 differentially expressed genes (DEGs) and 203 differentially expressed long non-coding RNAs (DE-lncRNAs) were identified between atrial fibrillation recurrence group and sinus rhythm maintenance group. Gene Ontology (GO) analysis showed that DEGs were enriched in “regulation of immune response”, and “regulation of immune system process” for biological processes (BP), enriched in “extracellular matrix”, “cell-cell junction” for cellular components (CC), and enriched in “signaling adaptor activity”, “protein-macromolecule adaptor activity” for molecular functions (MF). For KEGG analysis, DEGs are associated with “PI3K-Akt signaling pathway”, “MAPK signaling pathway”. 9 hub genes (MMP9, IGF2, FGFR1, HSPG2, GZMB, PEG10, GNLY, COL6A1, and KCNE3) were identified through the Protein-Protein Interaction network. LncRNA-TMEM51-AS1-201 was identified as a core regulator and may impact AF recurrence after catheter ablation by regulating “COL6A1, FGFR1, HSPG2, and IGF2.”
Project description:Left atrial-esophageal fistula (LAEF) is a rare complication of radiofrequency ablation (RFA) procedures undertaken for atrial fibrillation (AF). This complication is associated with significant morbidity and mortality. Currently, there is no clear consensus on the appropriate management strategy. We report a case of a LAEF that developed in a patient 2 weeks after RFA for medication refractory AF. The patient underwent successful repair of the fistula through a left posterolateral thoracotomy, wherein the esophageal and atrial lesions were repaired primarily with an intercostal muscle flap and bovine pericardial patch to reinforce and prevent recurrence.