title: P-wave indices and atrial fibrillation: cross-cohort assessments from the Framingham Heart Study (FHS) and Atherosclerosis Risk in Communities (ARIC) study.
abstract: BACKGROUND
  Atrial fibrillation (AF) is associated with increased morbidity. P-wave indices (PWIs) measure atrial electrical function and are associated with AF. Study of PWI has been limited to single-cohort investigations, and their contributions to risk enhancement are unknown.
  
  
  METHODS
  We examined PWI from the FHS and ARIC study. We calculated 10-year AF risk using adjusted Cox models. We conducted cross-cohort meta-analyses for the PWI estimates and assessed their contributions to risk discrimination (c statistic), net reclassification index, and integrated discrimination improvement.
  
  
  RESULTS
  After exclusions, the analysis included 3,110 FHS (62.6 ± 9.8 years, 56.9% women) and 8,254 ARIC participants (62.3 ± 5.6 years, 57.3% women, 20.3% black race). Over 10 years, 217 FHS and 458 ARIC participants developed AF. In meta-analysis, P-wave duration >120 milliseconds was significantly associated with AF (hazard ratio 1.55, 95% CI 1.29-1.85) compared with ≤120 milliseconds. P-wave area was marginally but not significantly related to AF (hazard ratio 1.31, 95% CI 0.95-1.80). P-wave terminal force was strongly associated with AF in ARIC but not FHS. P-wave indices had a limited contribution toward predictive risk beyond traditional risk factors and markers.
  
  
  CONCLUSIONS
  P-wave indices are intermediate phenotypes for AF. They are associated with AF in cross-cohort meta-analyses but contribute minimally toward enhancing risk prediction.
authors.affiliation: Section of Cardiovascular Medicine, Boston University School of Medicine, Boston, MA; National Heart Lung and Blood Institute's Framingham Heart Study, Framingham, MA. Electronic address: jmagnani@bu.edu.
authors.forename: Jared W
authors.initials: JW
authors.lastname: Magnani
authors.affiliation: Department of Mathematics and Statistics, Boston University, Boston, MA.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN.
authors.forename: Faye
authors.initials: F
authors.lastname: Lopez
authors.affiliation: National Heart Lung and Blood Institute's Framingham Heart Study, Framingham, MA; Duke Clinical Research Institute, Duke University, Durham, NC; Department of Mathematics and Statistics, Boston University, Boston, MA; Department of Biostatistics, Boston University School of Public Health, Boston, MA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pencina
authors.affiliation: Johns Hopkins University, Baltimore, MD.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Agarwal
authors.affiliation: Epidemiological Cardiology Research Center (EPICARE), Department of Epidemiology and Prevention, Wake Forest University School of Medicine, Winston-Salem, NC.
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
authors.affiliation: Section of Cardiovascular Medicine, Boston University School of Medicine, Boston, MA; National Heart Lung and Blood Institute's Framingham Heart Study, Framingham, MA; Department of Epidemiology, Boston University School of Public Health, Boston, MA.
authors.forename: Emelia J
authors.initials: EJ
authors.lastname: Benjamin
authors.affiliation: Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Alonso
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology / Q000503:physiopathology*; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D016016:Proportional Hazards Models; D014481:United States / Q000453:epidemiology