title: Effect of percutaneous coronary intervention of nonacute total coronary artery occlusions on QT dispersion.
abstract: BACKGROUND
  Myocardial ischemia is one of several potential causes of increased QT dispersion (QTd) in patients with nonacute total coronary artery occlusions (TCOs). We sought to assess the effect of percutaneous revascularization (PCI) of TCO on QTd and the relationship between QTd and long-term vessel patency.
  
  
  METHODS
  Seventy patients enrolled in the TOSCA were analyzed. Patients were undergoing PCI of a TCO > 72 hours' duration. Two independent reviewers measured QTd from electrocardiograms done immediately before PCI (PRE), 12 to 18 hours after PCI (POST), and then at 6 months (6M). Follow-up angiography was performed at 6 months.
  
  
  RESULTS
  Mean QTd decreased from PRE (77 +/- 29 milliseconds) to POST (66 +/- 26 milliseconds, P < .001) and 6M (65 +/- 25 milliseconds, P < .001). Patients with the same or longer QTd at 6 months compared with POST (POST < or = 6M) had significantly higher risk of failed target-vessel patency (odds ratio 10.3, 95% CI 1.24-84.8) than patients with QTd reduction at 6M versus POST values.
  
  
  CONCLUSIONS
  Revascularization of TCO resulted in a decrease in QTd, which was sustained at 6M. This suggests that PCI to a TCO has a beneficial effect on stabilization of the underlying ischemic substrate. Furthermore, absence of QTd reduction at 6M versus POST was associated with increased risk of failed target-vessel patency.
authors.affiliation: Department of Medicine, University of Calgary, Calgary Health Region, Alberta, Canada. david.goodhart@calgaryhealthregion.ca
authors.forename: David M
authors.initials: DM
authors.lastname: Goodhart
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Hubacek
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Anderson
authors.forename: Hank
authors.initials: H
authors.lastname: Duff
authors.forename: Gerald
authors.initials: G
authors.lastname: Barbeau
authors.forename: John
authors.initials: J
authors.lastname: Ducas
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Carere
authors.forename: Charles
authors.initials: C
authors.lastname: Lazzam
authors.forename: Vladimir
authors.initials: V
authors.lastname: Dzavik
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Buller
authors.forename: Mouhieddin
authors.initials: M
authors.lastname: Traboulsi
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy*; D004562:Electrocardiography; D006801:Humans; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology; D013997:Time Factors