Document Detail

Myocardial perfusion imaging findings and the role of adenosine in the warm-up angina phenomenon.
MedLine Citation:
PMID:  11216964     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: This study examined the roles of myocardial perfusion and adenosine in warm-up angina. BACKGROUND: In warm-up angina, neither the role of an adenosine-mediated mechanism, as is found in experimental ischemic preconditioning, nor of increased myocardial perfusion is well defined. METHODS: In substudy A, a single-photon emission computed tomography (SPECT)-thallium-201 exercise test was performed by 12 subjects with ischemic heart disease on three occasions one week apart. The third test was preceded by a warm-up test. The extent of the thallium deficit and its intensity on the third test were compared with the baseline tests controlling for the heart rate-systolic blood pressure product (RPP) at thallium injection. In substudy B, 12 similar subjects did two successive exercise tests at two separate sessions and received the adenosine antagonist, aminophylline (intravenous 5 mg/kg bolus and 0.9 mg/kg/h infusion) at one session, and equivalent saline at the other session. Change in ischemic threshold (RPP at 1 mm ST segment depression) and in maximum ST depression adjusted for RPP were analyzed. RESULTS: In substudy A, despite a significant attenuation of electrocardiogram indexes of myocardial ischemia between the baseline and third (warmed-up) tests, the thallium extent deficits (20.8 +/- 15.1% and 16.8 +/- 12.4%) and intensity deficits (41.2 +/- 12.6% and 39.3 +/- 12.6%) did not differ significantly. In substudy B, the increase in ischemic threshold on re-exercise was unaffected by aminophylline. Adjusted maximum ST depression even decreased to a greater extent on re-exercise with aminophylline (by 51 +/- 21%) than with saline (by 32 +/- 19%) (p = 0.012). CONCLUSIONS: While warm-up angina is associated with a significant attenuation of exercise electrocardiogram indexes of ischemia, it is unaccompanied by significant changes in SPECT perfusion and does not appear to be mediated by an adenosine-dependent mechanism since it is not blocked by aminophylline. Thus, its mechanism, which appears distinct from experimental ischemic preconditioning, remains unidentified.
P Bogaty; J G Kingma; J Guimond; P Poirier; L Boyer; L Charbonneau; G R Dagenais
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of the American College of Cardiology     Volume:  37     ISSN:  0735-1097     ISO Abbreviation:  J. Am. Coll. Cardiol.     Publication Date:  2001 Feb 
Date Detail:
Created Date:  2001-02-16     Completed Date:  2001-03-01     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  8301365     Medline TA:  J Am Coll Cardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  463-9     Citation Subset:  AIM; IM    
Quebec Heart Institute/Laval Hospital, Laval University, Sainte-Foy, Canada.
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MeSH Terms
Adenosine / physiology*
Aminophylline / administration & dosage
Angina Pectoris / physiopathology,  radionuclide imaging*
Blood Pressure / physiology
Coronary Disease / physiopathology,  radionuclide imaging*
Electrocardiography / drug effects
Exercise Test*
Heart Rate / physiology
Ischemic Preconditioning, Myocardial
Middle Aged
Predictive Value of Tests
Systole / physiology
Tomography, Emission-Computed, Single-Photon*
Reg. No./Substance:
317-34-0/Aminophylline; 58-61-7/Adenosine

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