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Blood flow heterogeneity in the heart
1Institut für Physiologie Medizinische Fakultät Carl Gustav Carus, TU Dresden, Germany.
Basic Research in Cardiology
|January 8, 1999
Summary
Myocardial blood flow is uneven even in healthy tissue. This spatial heterogeneity, influenced by factors like sample size, is stable over time and linked to local aerobic metabolism.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Myocardial Perfusion Imaging
Background:
- Local microsphere deposition density in myocardium is heterogeneous under physiological conditions.
- Biological heterogeneity must be distinguished from methodological factors like injection volume, regional blood flow, and sample mass.
Purpose of the Study:
- To investigate the nature and contributing factors of spatial heterogeneity in myocardial blood flow.
- To differentiate biological heterogeneity from methodological influences on microsphere deposition.
Main Methods:
- Analysis of microsphere deposition density variability using coefficients of variation (CV) for spatial (spat), temporal (temp), and methodological (meth) factors.
- Fractal and autocorrelation analyses to assess spatial correlation of myocardial blood flow.
- Comparison of metabolic markers between low and high flow myocardial regions.
Main Results:
- Spatial flow heterogeneity is the largest contributor to observed variability in microsphere deposition density.
- This heterogeneity is independent of myocardial layer, increases with decreasing sample mass and mean flow.
- Myocardial blood flow exhibits spatial correlation and is nonrandom.
- Local blood flow correlates with metabolic and transport rates, but not with markers of tissue hypoxia.
Conclusions:
- Histologically homogeneous myocardium exhibits inherent spatial blood flow heterogeneity.
- This heterogeneity is temporally stable, resolution-dependent, largely layer-independent, nonrandom, and linked to local aerobic metabolism.