title: Genomic Contributors to Rhythm Outcome of Atrial Fibrillation Catheter Ablation - Pathway Enrichment Analysis of GWAS Data.
abstract: BACKGROUND
  Left atrial enlargement and persistent atrial fibrillation (AF) are well-known predictors for arrhythmia recurrence after AF catheter ablation (LRAF). In this study, by using pathway enrichment analysis of GWAS data, we tested the hypothesis that genetic pathways associated with these phenotypes are also associated with LRAF.
  
  
  METHODS
  Samples from 660 patients with paroxysmal (n = 370) or persistent AF (n = 290) undergoing de-novo AF catheter ablation were genotyped for ~1,000,000 SNPs. SNPs found to be significantly associated with left atrial diameter (LAD) or AF type were used for gene-based association tests in a systematic biological Knowledge-based mining system for Genome-wide Genetic studies (KGG). Associated genes were tested for pathway enrichment using WEB-based Gene SeT AnaLysis Toolkit (WebGestalt), the Gene Annotation Tool to Help Explain Relationships (GATHER) and the databases provided by Kyoto Encyclopedia of Genes and Genomes (KEGG). In a second step, the association of consistently enriched pathways and LRAF was tested.
  
  
  RESULTS
  By using sequential 7-day Holter ECGs, LRAF between 3 and 12 months was observed in 48% and was associated with LAD (B = 1.801, 95% CI 0.760-2.841, p = 1.0E-3) and persistent AF (OR = 2.1; 95% CI 1.567-2.931, p = 2.0E-6). WebGestalt (adj. p = 2.7E-22) and GATHER (adj. p = 5.2E-3) identified the calcium signaling pathway (hsa04020) as the only consistently enriched pathway for LAD, while the extracellular matrix (ECM) -receptor interaction pathway (hsa04512) was the only consistently enriched pathway for AF type (adj. p = 2.1E-15 in WebGestalt; adj. p = 9.3E-4 in GATHER). Both calcium signaling (adj. p = 2.2E-17 in WebGestalt; adj. p = 2.9E-2 in GATHER) and ECM-receptor interaction (adj. p = 1.2E-10 in WebGestalt; adj. p = 2.9E-2 in GATHER) were significantly associated with LRAF.
  
  
  CONCLUSIONS
  Calcium signaling and ECM-receptor interaction pathways are associated with LAD and AF type and, in turn, with LRAF. Future and larger studies are necessary to replicate and apply these findings.
authors.affiliation: Department of Electrophysiology, Heart Center Leipzig, Leipzig University, Leipzig, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Husser
authors.affiliation: Department of Electrophysiology, Heart Center Leipzig, Leipzig University, Leipzig, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Büttner
authors.affiliation: Department of Electrophysiology, Heart Center Leipzig, Leipzig University, Leipzig, Germany.
authors.forename: Laura
authors.initials: L
authors.lastname: Ueberham
authors.affiliation: Department of Electrophysiology, Heart Center Leipzig, Leipzig University, Leipzig, Germany.
authors.forename: Borislav
authors.initials: B
authors.lastname: Dinov
authors.affiliation: Department of Electrophysiology, Heart Center Leipzig, Leipzig University, Leipzig, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Sommer
authors.affiliation: Department of Electrophysiology, Heart Center Leipzig, Leipzig University, Leipzig, Germany.
authors.forename: Arash
authors.initials: A
authors.lastname: Arya
authors.affiliation: Department of Electrophysiology, Heart Center Leipzig, Leipzig University, Leipzig, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hindricks
authors.affiliation: Department of Electrophysiology, Heart Center Leipzig, Leipzig University, Leipzig, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bollmann
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000235:genetics / Q000503:physiopathology / Q000601:surgery; D020013:Calcium Signaling / Q000235:genetics*; D017115:Catheter Ablation; D004569:Electroencephalography; D005109:Extracellular Matrix / Q000235:genetics*; D005260:Female; D055106:Genome-Wide Association Study; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence