title: A blunted heart rate response to regadenoson is an independent prognostic indicator in patients undergoing myocardial perfusion imaging.
abstract: BACKGROUND
  Regadenoson myocardial perfusion imaging (MPI) is a useful method for risk assessment. We hypothesized that the heart rate response (HRR) to regadenoson carries incremental prognostic information to that derived from perfusion pattern and left ventricular (LV) ejection fraction (EF).
  
  
  RESULTS
  The study population included 1,156 (60 ± 13 years, 46% women, 40% diabetes mellitus, 53% chronic kidney disease) patients. During a follow-up period of 22 ± 5 months, 103 patients died (9%). Independent determinants of the HRR included age, gender, race, diabetes mellitus, coronary revascularization, LVEF, use of insulin and aldosterone antagonists. Decreasing HRR was associated with stepwise increase in mortality (log-rank P < .0001). In a Cox proportional model for mortality that adjusted for age, gender, diabetes mellitus, renal disease, and MPI findings, HRR in the lowest quartile was independently associated with fivefold increase in mortality compared to the highest quartile [HR 5.2, 95% CI 2.3-12.0, P < .0001]. Patients with a normal HRR had a relatively low annualized total mortality despite the presence of risk factors. The addition of HRR to traditional MPI findings had a net reclassification improvement of 15%, P = .02.
  
  
  CONCLUSIONS
  A blunted HRR to regadenoson is an independent predictor of poor outcome, adds incremental value to MPI, and helps in better risk stratification.
authors.affiliation: Division of Cardiovascular Disease, University of Alabama at Birmingham, AL 35294, USA. fadihage@uab.edu
authors.forename: Fadi G
authors.initials: FG
authors.lastname: Hage
authors.forename: Phillip
authors.initials: P
authors.lastname: Dean
authors.forename: Fahad
authors.initials: F
authors.lastname: Iqbal
authors.forename: Jaekyeong
authors.initials: J
authors.lastname: Heo
authors.forename: Ami E
authors.initials: AE
authors.lastname: Iskandrian
mesh_terms: D058917:Adenosine A2 Receptor Antagonists / Q000627:therapeutic use; D000407:Alabama / Q000453:epidemiology; D005080:Exercise Test / Q000706:statistics & numerical data; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000706:statistics & numerical data*; D015995:Prevalence; D011379:Prognosis; D011687:Purines; D011720:Pyrazoles; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013318:Stroke Volume / Q000187:drug effects*; D016019:Survival Analysis; D015996:Survival Rate; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000401:mortality*
chemical_list: D058917:Adenosine A2 Receptor Antagonists; D011687:Purines; D011720:Pyrazoles; C430916:regadenoson