title: ST changes before and during primary percutaneous coronary intervention predict final infarct size in patients with ST elevation myocardial infarction.
abstract: BACKGROUND
  In patients with ST elevation myocardial infarction (STEMI), spontaneous ST resolution (spontSTR) is a marker of successful microvascular reperfusion. The significance of increase in ST elevation during reperfusion therapy (the ST peak phenomenon), however, is controversial.
  
  
  OBJECTIVE
  The purpose of the study was to evaluate whether preprocedural and periprocedural ST changes predict final infarct size (IS) in STEMI patients treated with primary percutaneous coronary intervention (primary PCI).
  
  
  METHODS
  Twelve-lead electrocardiograms (ECGs) were acquired in the prehospital phase and on admission in 200 STEMI patients transferred for primary PCI. Continuous ST monitoring was performed during and 90 minutes after primary PCI. The exact timing of interventional procedures and the resulting thrombolysis in myocardial infarction (TIMI) flow were registered. A 1-month single-photon emission computerized tomography was performed to evaluate IS. Patients were stratified into groups according to preprocedural and periprocedural ST changes as follows: patients with spontSTR before primary PCI and without (A) or with (B) ST peak during primary PCI and patients with persistent ST elevation before primary PCI and without (C) or with (D) ST peak during primary PCI.
  
  
  RESULTS
  Groups A (n = 45), B (n = 10), C (n = 109), and D (n = 36) differed with regard to IS (median, 2%, 3%, 13% vs 22% of the left ventricle; P < .0001). In multivariable analysis adjusting for baseline characteristics, preprocedural and periprocedural ECG findings and routine angiography findings, spontSTR was associated with smaller IS (B = -8.6%; P < .001), whereas the ST peak phenomenon was associated with larger IS (B = +5.0%; P = .006). There was no difference in TIMI flow grades in relation to coronary interventions among patients with and without ST peak during primary PCI.
  
  
  CONCLUSIONS
  In STEMI patients, spontSTR before primary PCI and the ST peak phenomenon during primary PCI predict minor vs extensive IS independent of angiographic patency grades. Further studies are needed to clarify whether the ST peak phenomenon is "a marker of injury before reperfusion" or "a marker of reperfusion-induced injury."
authors.affiliation: Department of Cardiology B, Aarhus University Hospital, Aarhus, Denmark. christian_juhl_terkelsen@hotmail.com
authors.forename: Christian Juhl
authors.initials: CJ
authors.lastname: Terkelsen
authors.forename: Anne Kjer
authors.initials: AK
authors.lastname: Kaltoft
authors.forename: Bjarne Linde
authors.initials: BL
authors.lastname: Nørgaard
authors.forename: Morten
authors.initials: M
authors.lastname: Bøttcher
authors.forename: Jens Flensted
authors.initials: JF
authors.lastname: Lassen
authors.forename: Karrina
authors.initials: K
authors.lastname: Clausen
authors.forename: Søren Steen
authors.initials: SS
authors.lastname: Nielsen
authors.forename: Leif
authors.initials: L
authors.lastname: Thuesen
authors.forename: Torsten Toftegaard
authors.initials: TT
authors.lastname: Nielsen
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Bøtker
authors.forename: Henning Rud
authors.initials: HR
authors.lastname: Andersen
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D004562:Electrocardiography / Q000379:methods*; D006801:Humans; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000601:surgery*; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome