title: The effect of exercise to P wave dispersion and its evaluation as a predictor of atrial fibrillation.
abstract: OBJECTIVE
  Prolongation of P wave time and increase of its dispersion as an independent predictor of atrial fibrillation. In patients with paroxysmal atrial fibrillation (PAF) as in healthy people, exercise augments sympathetic activity and therefore can cause the development of atrial fibrillation. The aim of this study is to evaluate the effect of exercise on P wave dispersion and to predict the development of atrial fibrillation.
  
  
  METHODS
  One hundred and ninety-eight patients (93 women, 105 men, mean age: 59.05 +/- 11.01 years) having the diagnosis of PAF were included in the study. The left atrial diameter of all these patients was more than 4.0 cm. One hundred and fifty-five patients (72 females, 83 males, mean age: 58.41 +/- 10.79 years), with left atrial diameter more than 4.0 cm and without PAF were taken as control group. Symptom limited exercise test with modified Bruce protocol was performed on all patients. Rest, maximum exercise and recovery, and first, third, and fifth-minute 12-derivation ECG was taken in all patients. The velocity of ECG was adjusted to 50 mm/s; shortest and largest P wave durations were measured and P wave dispersion was calculated.
  
  
  RESULTS
  The mean left atrial diameter was 4.41 +/- 0.58 cm in PAF patients and 4.38 +/- 0.48 cm in control group. No differences were found between PAF patients with the controls in exercise time (10.38 +/- 2.93 vs 10.81 +/- 2.75 minutes); METs (6.98 +/- 1.72 vs 7.28 +/- 1.75 minutes); resting heart rate (79.13 +/- 14.86 vs 79.69 +/- 10.43 bpm); peak heart rate (146.83 +/- 23.21 vs 146.94 +/- 16.13 bpm). Maximum exercise P wave duration and P wave dispersion were greater than the rest measurements in PAF group (respectively P < 0.0001 and P = 0.0004).
  
  
  CONCLUSIONS
  In PAF patients, P wave dispersion is significantly longer at rest, maximum exercise and recovery time than in a control group without PAF.
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000209:etiology; D016022:Case-Control Studies; D015331:Cohort Studies; D017548:Echocardiography, Transesophageal / Q000379:methods; D004562:Electrocardiography; D004594:Electrophysiology; D005080:Exercise Test / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D013997:Time Factors