title: ST-segment depression during vasodilator stress is of minor clinical importance in women with normal myocardial perfusion imaging and low or intermediate risk of coronary artery disease.
abstract: OBJECTIVE
  The prognostic value of electrocardiographic (ECG) ST-segment depression during vasodilator stress testing in patients with normal myocardial perfusion scintigraphy (MPS) is based on retrospective studies with controversial results. Moreover, the true incidence of obstructive coronary artery disease (CAD) in these patients is unknown.
  
  
  METHODS
  During a 33-month period, all consecutive patients referred for MPS were prospectively evaluated for interpretable ST-segment depression ≥ 1 mm during vasodilator stress testing. Of 1,687 patients with normal MPS and without known CAD, 109 (100 women) aged 65.2 ± 9.2 years demonstrated ST-segment shifts and formed the ECG-positive group. The pretest probability of CAD was low in 56%, intermediate in 39% and high in 5%. They were advised to proceed to coronary angiography. An equal number of patients with normal MPS and no ECG abnormalities matched for CAD predisposing factors comprised the control group. Follow-up of both groups was accomplished through a telephone interview.
  
  
  RESULTS
  Fifty-two patients from the ECG-positive group (48%) consented to coronary angiography. Six (11.5%) had obstructive CAD (≥50% lumen stenosis), one with left main artery disease, while three required revascularization. Follow-up was complete in 99 ECG-positive patients for a period of 20.6 ± 8.9 months. One hard event (non-fatal myocardial infarction) and one soft event (revascularization) were observed. No event was recorded in the control group.
  
  
  CONCLUSIONS
  In patients with low-intermediate risk of CAD, "ischaemic" ECG changes during vasodilator stress combined with normal MPS are encountered mostly in women and are associated with a low prevalence of significant CAD and a low cardiac event rate.
authors.affiliation: Department of Nuclear Medicine, University of Patras Medical School, University Hospital of Patras, Rion, Patras, Greece. dimap@med.upatras.gr
authors.forename: Dimitris J
authors.initials: DJ
authors.lastname: Apostolopoulos
authors.forename: Periklis
authors.initials: P
authors.lastname: Davlouros
authors.forename: Sotiria
authors.initials: S
authors.lastname: Alexiou
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Patsouras
authors.forename: Trifon
authors.initials: T
authors.lastname: Spyridonidis
authors.forename: Pavlos J
authors.initials: PJ
authors.lastname: Vassilakos
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Alexopoulos
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D012189:Retrospective Studies; D012306:Risk; D013312:Stress, Physiological / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D014665:Vasodilator Agents