Predictors of abnormal heart rate response to dipyridamole in patients undergoing myocardial perfusion SPECT

Objective To identify predictors of abnormal HR response to dipyridamole (DIP) in patients undergoing myocardial perfusion SPECT (MPS). Background Patients with a reduced heart rate (HR) response to DIP have higher cardiac mortality, but the mechanism is unknown. Methods We studied 432 patients who...

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Bibliographic Details
Published in:Annals of nuclear medicine 2011, Vol.25 (1), p.7-11
Main Authors: de Souza Leão Lima, Ronaldo, Machado, Luis, Azevedo, Alexandre B., De Lorenzo, Andrea
Format: Article
Language:English
Subjects:
Aged
Dipyridamole - pharmacology
Female
Heart Rate - drug effects
Humans
Imaging
Male
Medicine
Medicine & Public Health
Middle Aged
Myocardial Perfusion Imaging - methods
Nuclear Medicine
Original Article
Radiology
Stress, Physiological - drug effects
Tomography, Emission-Computed, Single-Photon - methods
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Summary:Objective To identify predictors of abnormal HR response to dipyridamole (DIP) in patients undergoing myocardial perfusion SPECT (MPS). Background Patients with a reduced heart rate (HR) response to DIP have higher cardiac mortality, but the mechanism is unknown. Methods We studied 432 patients who underwent dual-isotope gated MPS. DIP (0.56 mg/kg) was infused over 4 min, and Tc-99m tetrofosmin was injected 3 min after the end of the infusion. MPS was semiquantitatively interpreted. Left ventricular ejection fraction (LVEF) and volumes were automatically calculated. The population was categorized into quartiles according to HR ratio, and characteristics in each quartile were compared. Logistic regression analysis was performed to identify predictors of abnormal HR response, using the lowest quartile as the independent variable. Results Patients with abnormal HR response were more frequently without chest pain, with a history of chronic renal failure and taking digoxin. Baseline HR was higher and had fewer symptoms during stress. The stress and rest perfusion defects were greater, but reversibility was not; in addition, LVEF was lower. Multivariable logistic regression analysis demonstrated that the independent predictors of abnormal HR response were baseline HR and low LVEF. Conclusions LV dysfunction is an independent predictor of abnormal HR response to DIP, and the association between low LVEF and low HR ratio may explain the link between abnormal HR ratio and increased mortality.
ISSN:0914-7187
1864-6433
DOI:10.1007/s12149-010-0420-8