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Characterization of the functional border zone around regionally ischemic myocardium using circumferential
Journal of the American College of Cardiology
|July 1, 1986
Summary
A functional border zone in the heart muscle (myocardium) surrounding ischemic areas exists but is small. This zone shows normal blood flow but impaired contraction, indicating discrete functional changes in ischemic heart disease.
Area of Science:
- Cardiology
- Myocardial Physiology
Background:
- Previous studies suggest a functional border zone in myocardium adjacent to ischemic areas.
- This zone exhibits normal perfusion but abnormal contractile function.
Purpose of the Study:
- To define the spatial characteristics of the myocardial functional border zone.
- To compare the extent of hypoperfusion and hypofunction in ischemic myocardium.
Main Methods:
- Utilized two-dimensional echocardiography for left ventricular function mapping.
- Employed radioactive microspheres and autoradiography for coronary flow and hypoperfusion zone measurement in dogs.
- Assessed circumferential left ventricular wall thickening at 22.5-degree intervals.
Main Results:
- The hypofunctional zone (abnormal contraction) was significantly larger than the hypoperfusion zone (reduced blood flow).
- This indicates a region of normally perfused but abnormally contracting muscle surrounding the ischemic area.
- The functional border zone was found to be relatively small, measuring approximately 8-9 mm on lateral borders.
Conclusions:
- A functional border zone lateral to ischemic myocardium exists.
- This zone is characterized by normal perfusion but impaired contractility.
- The border zone in this canine model is discrete and relatively small.