Myocardial kinetics of thallium-201 after stress in normal and perfusion-reduced canine myocardium
Despite the emerging use of quantitative computer programs for assessing myocardial thallium uptake and clearance after exercise, little is known about the kinetics of thallium after exercise stress. Accordingly, 11 mongrel dogs with experimental left anterior descending coronary stenoses were given thallium during norepinephrine infusion to simulate exercise. The infusion was discontinued and thallium activity was monitored regionally using miniature radiation detectors for 3 hours. Heart rate, arterial pressure and double product all increased significantly during norepinephrine infusion. The mean fractional myocardial thallium clearance was lower (0.47 +/- 0.03 (+/- standard error of the mean)) for the stenosis zone than for the no-stenosis zone (0.57 +/- 0.03) (p less than 0.0001). The stress blood flow ratio (stenosis/no-stenosis zone = 0.27 +/- 0.06) was significantly lower than the final thallium activity ratio (0.68 +/- 0.07) (p less than 0.001), consistent with thallium redistribution occurring over the 3-hour period. Myocardial thallium activity in the stenosis zone peaked in a mean of 2.2 minutes, then washed out biexponentially with a final decay constant of 0.0035 +/- 0.0005 min-1. Myocardial thallium activity in the no-stenosis zone peaked within 1 minute in all dogs, then washed out biexponentially, with a final decay constant of 0.0043 +/- 0.0003 (p less than 0.001 compared with stenosis zone). In conclusion, fractional clearance of thallium can differentiate myocardium distal to a coronary artery stenosis from that supplied by a normal coronary vessel.
- OSTI ID:
- 5801903
- Journal Information:
- Am. J. Cardiol.; (United States), Journal Name: Am. J. Cardiol.; (United States) Vol. 15; ISSN AJCDA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Kinetics of thallium-201 in reperfused canine myocardium after coronary artery occlusion
Limitations of regional myocardial thallium clearance for identification of disease in individual coronary arteries
Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADRENAL HORMONES
ANIMALS
ARTERIES
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BLOOD FLOW
BLOOD PRESSURE
BLOOD VESSELS
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
CLEARANCE
CORONARIES
DAYS LIVING RADIOISOTOPES
DOGS
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
EXERCISE
HEART
HEAVY NUCLEI
HORMONES
INFUSION
INTAKE
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MUSCLES
MYOCARDIUM
NEUROREGULATORS
NORADRENALINE
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIOISOTOPES
RADIONUCLIDE KINETICS
SECONDS LIVING RADIOISOTOPES
STEROID HORMONES
SYMPATHOMIMETICS
THALLIUM 201
THALLIUM ISOTOPES
UPTAKE
VERTEBRATES