title: Prognostic value of exercise-induced QT dispersion in patients after acute myocardial infarction.
abstract: BACKGROUND
  Electrocardiographic exercise tests are widely recommended for patients before discharge after myocardial infarction, what justify the search for new variables which may improve their prognostic value. QT dispersion in 12 lead ECG reflects the heterogeneity of ventricular repolarisation. Increased QT dispersion is a noninvasive marker of ischaemia and electrical instability.
  
  
  OBJECTIVE
  Evaluation of the prognostic value of exercise-induced changes of QT dispersion in patients after an acute myocardial infarction.
  
  
  METHODS
  Heart rate limited treadmill exercise test according to modified Bruce was performed 14+/-5 days after infarction in 77 patients (age 56+/-11,8 female). QT dispersion was measured at rest and on peak exercise. Patients were followed up for mean 88 months.
  
  
  RESULTS
  QT dispersion was higher at peak exercise in those patients who died due to cardiovascular causes (n=8) or suffered from non-fatal myocardial infarction during follow-up (n=15), than in remaining group (71+/-20 vs 58+/-22 msec, p<0.01). At rest QT dispersion was similar in both groups (64+/-17 vs 66+/-20 msec, NS).
  
  
  CONCLUSIONS
  The lack of an exercise-induced decrease in QT dispersion identifies a subgroup of patients after myocardial infarction with a poor long-term prognosis.
authors.affiliation: Department of Cardiology, Postgraduate Medical School, Warsaw, Poland.
authors.forename: Bronisław
authors.initials: B
authors.lastname: Bednarz
authors.forename: Robert
authors.initials: R
authors.lastname: Wołk
authors.forename: Tomasz
authors.initials: T
authors.lastname: Chamiec
authors.forename: Leszek
authors.initials: L
authors.lastname: Ceremuzyński
mesh_terms: D000368:Aged; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D012680:Sensitivity and Specificity; D013997:Time Factors