ORIGINAL ARTICLE Diagnostic and prognostic significance of ischemic electrocardiographic changes with regadenoson-stress myocardial perfusion imaging Rami Doukky, MD, MSc, FACC, FASNC,a,b Adebayo Olusanya, MD,a Raj Vashistha, MD,a Abhimanyu Saini, MD,a Ibtihaj Fughhi, MD,b Khaled Mansour, MD,a Abiy Nigatu, MD,c Kara Confer, BS,d and Shannon A. Sims, MD, PHDd a

Division of Cardiology, John H. Stroger, Jr. Hospital of Cook County, Chicago, IL Division of Cardiology, Rush University Medical Center, Chicago, IL c Department of Medicine, John H. Stroger, Jr. Hospital of Cook County, Chicago, IL d Department of Medicine, Rush University Medical Center, Chicago, IL b

Received Feb 14, 2014; accepted Dec 4, 2014 doi:10.1007/s12350-014-0047-6

Background. The diagnostic and prognostic value of regadenoson-induced ST-segment depression (ST;) is not defined. Due to the low incidence of ST; ‡1.0 mm with vasodilator stress, a lower threshold to define ischemic ECG response may provide improved clinical utility. Methods. We conducted a retrospective cohort study of patients who underwent regadenosonstress SPECT myocardial perfusion imaging (MPI) followed by coronary angiography within 6 months. Ischemic ST; was defined as ‡0.5 mm. The prevalence of angiographically severe coronary artery disease (CAD) and the rates of major adverse cardiac events (MACE) including cardiac death, myocardial infarction, and coronary revascularization were determined. Results. In a diagnostic cohort of 629 subjects, 117 (18.6%) had ST; ‡0.5 mm. Severe CAD was more prevalent in the ST; ‡0.5 vs ST