Relationship between blood flow, tissue viability, and lethal ventricular arrhythmias in the infarcted dog heart
The standard method for measuring myocardial blood flow (MBF) with radioactive microspheres requires processing of selected tissue samples and consequent loss of exact relation to myocardial morphology. Also, in myocardial infarction (MI) there are inaccuracies due to overlap of tissues from borders of normal and MI. A computer-based image processing method using Tc-99m microspheres (20 ..mu..) for quantitative analysis of MBF in dogs was developed which delineated zones of differing MBF and confirmed the increase of MBF in surviving myocardium with healing. Despite extensive use of thallium-201 (TI-201) for myocardial imaging, the impact of ischemic injury on myocardial accumulation and release of TI-201 independent of flow is not well-understood. Therefore, myocardial uptake and clearance of TI-201 in response to ischemic injury was assessed in vitro using isolated left ventricular sections, 24 hours or 4 days after coronary occlusion. The results indicate that there was a faster washout rate of TI-201 from the ischemically-injured myocardial cells. Since the geologic properties of thallium closely resemble those of potassium and the excessive accumulation of extracellular concentration of potassium ((K/sup +/)/sub 0/) is clinically important in the genesis of cardiac arrhythmias, the TI-201 ions may thus serve as a marker of this increased (K/sup +/)/sub 0/. The findings suggest ischemically-injured myocardial cells became increasingly leaky for the potassium efflux. Thus, TI-201 redistribution is not related to a more rapid washout of the radionuclide from normal myocardial cells, but rather due to a more efficient extraction of the monovalent cation with more prolonged circulatory exposure in the ischemic area, and a gradual release of TI-201 from the nonischemic zone.
- Research Organization:
- Oklahoma Univ., Oklahoma City (USA). Health Sciences Center
- OSTI ID:
- 6066607
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Myocardial neutrophil accumulation during reperfusion after reversible or ischemic injury
Relationship of ventricular arrhythmias to the angiographically and scintigraphically estimated extent of ventricular damage late after myocardial infarction
Related Subjects
BLOOD FLOW
MEASURING METHODS
MYOCARDIAL INFARCTION
BIOLOGICAL MARKERS
TECHNETIUM 99
TISSUE DISTRIBUTION
THALLIUM 201
RETENTION
ANIMAL TISSUES
DOGS
EXPERIMENTAL DATA
HEART
IMAGE PROCESSING
IMAGES
IN VITRO
ISOMERIC NUCLEI
MICROSPHERES
MYOCARDIUM
UPTAKE
VIABILITY
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARDIOVASCULAR DISEASES
CARDIOVASCULAR SYSTEM
DATA
DAYS LIVING RADIOISOTOPES
DISEASES
DISTRIBUTION
ELECTRON CAPTURE RADIOISOTOPES
HEAVY NUCLEI
HOURS LIVING RADIOISOTOPES
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MUSCLES
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANS
PROCESSING
RADIOISOTOPES
SECONDS LIVING RADIOISOTOPES
TECHNETIUM ISOTOPES
THALLIUM ISOTOPES
TISSUES
VERTEBRATES
YEARS LIVING RADIOISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics