title: Depressed heart rate response to vasodilator stress for myocardial SPECT predicts mortality in patients after myocardial infarction.
abstract: BACKGROUND
  As heart rate (HR) response during vasodilator stress myocardial perfusion studies can be a marker of HR variability, we investigated its prognostic value in patients after myocardial infarction (MI).
  
  
  METHODS
  Subjects were 147 survivors of MI who underwent vasodilator stress thallium-201 scintigraphy. HR response was measured as peak to basal (P/B) ratios during vasodilator infusion. End points for survival analysis were all-cause deaths, non-fatal recurrent MI, and soft events.
  
  
  RESULTS
  HR response was significantly depressed in the post-MI patients compared to controls (p<0.0005). HR response correlated to LVEF (r=0.37, p<0.0001) and summed stress scores (r=-0.18, p<0.05), but not with antianginal medication. During 58+/-30 mo of follow-up, there were 15 deaths, 7 recurrent MI, and 11 soft events. Low HR response, old age, low LVEF, and high difference score were significant univariate risk factors for death. Multivariate analysis identified low HR response (p=0.03), high stress score (p=0.02), and low LVEF (p=0.05) as independent predictors of mortality. The predictive value of HR response was incremental to that offered by other variables (p=0.02).
  
  
  CONCLUSIONS
  HR response, readily attained during vasodilator stress myocardial perfusion studies, may provide useful additional prognostic information in post-MI patients.
authors.affiliation: Department of Nuclear medicine, Sungkyunkwan University School of Medicine, Samsung Medical Center, 135-710, Seoul, Republic of Korea.
authors.forename: Young Hwan
authors.initials: YH
authors.lastname: Kim
authors.forename: Kyung-Han
authors.initials: KH
authors.lastname: Lee
authors.forename: Hong Joo
authors.initials: HJ
authors.lastname: Chang
authors.forename: Eun Jeong
authors.initials: EJ
authors.lastname: Lee
authors.forename: Hyun Woo
authors.initials: HW
authors.lastname: Chung
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Yong
authors.initials: Y
authors.lastname: Choi
authors.forename: Yearn Seong
authors.initials: YS
authors.lastname: Choe
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Lee
authors.forename: Byung-Tae
authors.initials: BT
authors.lastname: Kim
mesh_terms: D000704:Analysis of Variance; D004176:Dipyridamole; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D053208:Kaplan-Meier Estimate; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000401:mortality* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012008:Recurrence; D012107:Research Design; D012189:Retrospective Studies; D018570:Risk Assessment; D013794:Thallium Radioisotopes; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D014665:Vasodilator Agents; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D013794:Thallium Radioisotopes; D014665:Vasodilator Agents; D004176:Dipyridamole