Depressed heart rate response to vasodilator stress for myocardial SPECT predicts mortality in patients after myocardial infarction.
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.
Kim
Young Hwan
YH
Department of Nuclear medicine, Sungkyunkwan University School of Medicine, Samsung Medical Center, 135-710, Seoul, Republic of Korea.
Lee
Kyung-Han
KH
Chang
Hong Joo
HJ
Lee
Eun Jeong
EJ
Chung
Hyun Woo
HW
Choi
Joon Young
JY
Choi
Yong
Y
Choe
Yearn Seong
YS
Lee
Sang Hoon
SH
Kim
Byung-Tae
BT
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
D013794:Thallium Radioisotopes; D014665:Vasodilator Agents; D004176:Dipyridamole