title: Early reduction of QT dispersion after primary percutaneous intervention in ST-segment elevation acute myocardial infarction. Mechanisms and clinical implications.
abstract: OBJECTIVE
  To determine, in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PPCI), the mechanisms and clinical implications of the acute changes in QT dispersion (QTd).
  
  
  METHODS
  In this prospective study we included 216 patients admitted with a STEMI of <12 h of evolution. All were treated with PPCI. QTd was measured prior to PPCI and within 1 h after.
  
  
  RESULTS
  The ratio of QTd reduction after PPCI (QTd-R) - defined as [(QTd before PPCI - QTd after PPCI)/QTd before PPCI] x100 - was significantly correlated with the percentage of ST-segment elevation resolution (ST-R; p < 0.001). To determine the significance of the different values of QTd-R, we further subdivided our population into 3 groups according to the tertiles of QTd-R (<10, 11-49, > or =50%). Patients with longer QTd-R had higher percentages of ST-R: 32 +/- 43 for QTd-R <10% vs. 60 +/- 21 for 11-49% vs. 71 +/- 12 for > or =50% (p < 0.05). By logistic regression, patients with QTd-R > or =50% had a reduction of 75% in the adjusted frequency of death or severe heart failure during hospitalization (95% CI 13-73%, p = 0.03).
  
  
  CONCLUSIONS
  QTd-R after PPCI occurs early, is closely related to the restoration of reperfusion at the microvascular level and provides additional prognostic information.
authors.affiliation: Department of Cardiology, University Hospital, Paseo de San Vicente 58 182, Salamanca, Spain. jimenezcandil@secardiologia.es
authors.forename: Javier
authors.initials: J
authors.lastname: Jiménez-Candil
authors.forename: Jesús
authors.initials: J
authors.lastname: Hernández Hernández
authors.forename: Víctor León
authors.initials: VL
authors.lastname: Aguero
authors.forename: Ana
authors.initials: A
authors.lastname: Martín
authors.forename: Francisco
authors.initials: F
authors.lastname: Martín
authors.forename: José Luis
authors.initials: JL
authors.lastname: Moríñigo
authors.forename: Cándido
authors.initials: C
authors.lastname: Martín-Luengo
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D004562:Electrocardiography / Q000379:methods* / Q000592:standards*; D005260:Female; D006333:Heart Failure / Q000401:mortality; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity