title: Effect of lifetime endurance training on left atrial mechanical function and on the risk of atrial fibrillation.
abstract: BACKGROUND
  Left atrium (LA) dilation and P-wave duration are linked to the amount of endurance training and are risk factors for atrial fibrillation (AF). The aim of this study was to evaluate the impact of LA anatomical and electrical remodeling on its conduit and pump function measured by two-dimensional speckle tracking echocardiography (STE).
  
  
  METHODS
  Amateur male runners >30 years were recruited. Study participants (n=95) were stratified in 3 groups according to lifetime training hours: low (<1500 h, n=33), intermediate (1500 to 4500 h, n=32) and high training group (>4500 h, n=30).
  
  
  RESULTS
  No differences were found, between the groups, in terms of age, blood pressure, and diastolic function. LA maximal volume (30±5, 33±5 vs. 37±6 ml/m(2), p<0.001), and conduit volume index (9±3, 11±3 vs. 12±3 ml/m(2), p<0.001) increased significantly from the low to the high training group, unlike the STE parameters: pump strain -15.0±2.8, -14.7±2.7 vs. -14.9±2.6%, p=0.927; conduit strain 23.3±3.9, 22.1±5.3 vs. 23.7±5.7%, p=0.455. Independent predictors of LA strain conduit function were age, maximal early diastolic velocity of the mitral annulus, heart rate and peak early diastolic filling velocity. The signal-averaged P-wave (135±11, 139±10 vs. 148±14 ms, p<0.001) increased from the low to the high training group. Four episodes of non-sustained AF were recorded in one runner of the high training group.
  
  
  CONCLUSIONS
  The LA anatomical and electrical remodeling does not have a negative impact on atrial mechanical function. Hence, a possible link between these risk factors for AF and its actual, rare occurrence in this athlete population, could not be uncovered in the present study.
authors.affiliation: Cardiology Department, Bern University Hospital, Bern, Switzerland. Electronic address: nicolas.brugger@insel.ch.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Brugger
authors.affiliation: Cardiology Department, Bern University Hospital, Bern, Switzerland.
authors.forename: René
authors.initials: R
authors.lastname: Krause
authors.affiliation: Cardiology Department, Bern University Hospital, Bern, Switzerland.
authors.forename: Frederik
authors.initials: F
authors.lastname: Carlen
authors.affiliation: Cardiology Department, Bern University Hospital, Bern, Switzerland.
authors.forename: Caroline
authors.initials: C
authors.lastname: Rimensberger
authors.affiliation: Cardiology Department, Bern University Hospital, Bern, Switzerland.
authors.forename: Ron
authors.initials: R
authors.lastname: Hille
authors.affiliation: Cardiology Department, Bern University Hospital, Bern, Switzerland.
authors.forename: Hélène
authors.initials: H
authors.lastname: Steck
authors.affiliation: Cardiology Department, Bern University Hospital, Bern, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Wilhelm
authors.affiliation: Cardiology Department, Bern University Hospital, Bern, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Seiler
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000328:Adult; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology*; D016279:Atrial Function, Left / Q000502:physiology*; D064752:Atrial Remodeling / Q000502:physiology*; D003430:Cross-Sectional Studies; D004452:Echocardiography; D004562:Electrocardiography; D005355:Fibrosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D012307:Risk Factors; D012420:Running / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology
keywords: Atrial fibrillation; Atrial function; Atrial remodeling; Endurance exercise training; Left atrium