title: Electrocardiographic changes during vasodilator SPECT myocardial perfusion imaging: does it affect diagnosis or prognosis?
abstract: BACKGROUND
  Significance of electrocardiographic (ECG) changes during vasodilator stress myocardial perfusion imaging (MPI) is controversial. We examined the diagnostic and prognostic significance of ECG changes during vasodilator single photon emission computerized tomography (SPECT) MPI.
  
  
  METHODS
  We studied consecutive patients who underwent vasodilator SPECT MPI from 1995 to 2009. Patients with baseline ECG abnormalities, previous history of coronary artery bypass graft surgery or myocardial infarction (MI) were excluded. Significant coronary artery disease (CAD) was defined as >70% stenosis of any vessel or ≥50% stenosis of left main. Mean follow-up was 2.4 ± 1.5 years for cardiac events (cardiac death and non-fatal MI).
  
  
  RESULTS
  Of patients in the diagnostic cohort, ST depression was associated with increased incidence of CAD with abnormal (P = .020 and P <.001) but not in those with normal perfusion (P = .342). Of 3,566 patients with follow-up in the prognostic cohort, including 130 (5.0%) with ST depression and normal perfusion, the presence of ST depression ≥1 mm did not affect the outcomes in any summed stress score category.
  
  
  CONCLUSIONS
  ST depression ≥1 mm during vasodilator SPECT MPI is associated with CAD in patients with abnormal perfusion, but provides no additional risk stratification beyond concomitant perfusion imaging, including those with normal studies.
authors.affiliation: Nuclear Cardiology Laboratory, Henry Low Heart Center, Division of Cardiology, Hartford Hospital, 80 Seymour Street, Hartford, CT 06102, USA. tazemi@harthosp.org
authors.forename: Talhat
authors.initials: T
authors.lastname: Azemi
authors.forename: Mridula
authors.initials: M
authors.lastname: Rai
authors.forename: Purvi
authors.initials: P
authors.lastname: Parwani
authors.forename: Sarkis
authors.initials: S
authors.lastname: Baghdasarian
authors.forename: Fawad
authors.initials: F
authors.lastname: Kazi
authors.forename: Alan W
authors.initials: AW
authors.lastname: Ahlberg
authors.forename: Giselle
authors.initials: G
authors.lastname: Cyr
authors.forename: Deborah
authors.initials: D
authors.lastname: Katten
authors.forename: David
authors.initials: D
authors.lastname: O'Sullivan
authors.forename: Daniel
authors.initials: D
authors.lastname: Fram
authors.forename: Gary V
authors.initials: GV
authors.lastname: Heller
mesh_terms: D000241:Adenosine; D000368:Aged; D003237:Connecticut / Q000453:epidemiology; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000401:mortality*; D004176:Dipyridamole; D004562:Electrocardiography / Q000706:statistics & numerical data*; D005080:Exercise Test; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000706:statistics & numerical data*; D011379:Prognosis; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D015899:Tomography, Emission-Computed, Single-Photon / Q000706:statistics & numerical data*; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D004176:Dipyridamole; D000241:Adenosine