ST changes before and during primary percutaneous coronary intervention predict final infarct size in patients with ST elevation myocardial infarction.
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."
Terkelsen
Christian Juhl
CJ
Department of Cardiology B, Aarhus University Hospital, Aarhus, Denmark. christian_juhl_terkelsen@hotmail.com
Kaltoft
Anne Kjer
AK
Nørgaard
Bjarne Linde
BL
Bøttcher
Morten
M
Lassen
Jens Flensted
JF
Clausen
Karrina
K
Nielsen
Søren Steen
SS
Thuesen
Leif
L
Nielsen
Torsten Toftegaard
TT
Bøtker
Hans Erik
HE
Andersen
Henning Rud
HR
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