title: High prevalence of atrial fibrillation in long-term endurance cross-country skiers: echocardiographic findings and possible predictors--a 28-30 years follow-up study.
abstract: BACKGROUND
  Lone atrial fibrillation (LAF) seems to be more common in endurance-trained male athletes than in men in the general population. The reason for this has not been found.
  
  
  OBJECTIVE
  To determine the prevalence of LAF in long-term endurance cross-country skiers and to examine possible predictors.
  
  
  METHODS
  Of 149 healthy, long-term trained cross-country skiers from three different age groups who were invited, 122 and 117 participated in the studies in 1976 and 1981, respectively. At follow-up in 2004-2006, 78 men participated, with 33 in age group I (54-62 years), 37 in group II (72-80 years) and eight in group III (87-92 years), whereas 37 individuals had died and seven could not be tracked. The examination programme applied in 1976, 1981 and 2004-2006 consisted of an electrocardiographic monitoring during rest and exercise and a maximal exercise test. Echocardiography was performed in 2004-2006.
  
  
  RESULTS
  A high prevalence (12.8%) of LAF was found. The only predictor from both 1976 and 1981 associated with LAF was a long PQ time (r=0.38, P=0.001 and r=0.27, P=0.02, respectively), whereas bradycardia was another predictor from 1981 (r=0.29, P=0.012). At follow-up, left atrial enlargement was a marker associated with LAF (P<0.001).
  
  
  CONCLUSIONS
  Long PQ time, bradycardia and left atrial enlargement seem to be important risk factors for LAF among long-term endurance cross-country skiers.
authors.affiliation: Department of Cardiac Rehabilitation, Feiringklinikken, Feiring, Norway. jostein.grimsmo@feiringklinikken.no
authors.forename: Jostein
authors.initials: J
authors.lastname: Grimsmo
authors.forename: Irene
authors.initials: I
authors.lastname: Grundvold
authors.forename: Sverre
authors.initials: S
authors.lastname: Maehlum
authors.forename: Harald
authors.initials: H
authors.lastname: Arnesen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology; D001919:Bradycardia / Q000150:complications / Q000453:epidemiology; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D005080:Exercise Test; D005500:Follow-Up Studies; D006325:Heart Atria / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D010807:Physical Endurance; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D012865:Skiing; D013997:Time Factors