Effect of aortic constriction on the functional border zone

Journal Article · Wed Apr 01 00:00:00 EST 1987 · Am. J. Physiol.; (United States)

OSTI ID:5877867

Gallagher, K P; Ning, X H; Gerren, R A; Drake, D H; Dunham, W R

To evaluate how aortic constriction affects nonischemic myocardium adjacent to the perfusion boundary (the functional border zone) the authors measured systolic wall thickening (dWT) with sonomicrometers in eight anesthetized, open-chest dogs. The locations of the wall thickening measurements relative to the perfusion boundary (PB) were determined with myocardial blood flow (radioactivity-labelled microspheres) maps constructed from multiple, small tissue samples. In nonischemic myocardium more than 10 mm from the PB produced by circumflex coronary occlusion, dWT increased significantly from 2.57 +/- 0.62 to 3.24 +/- 0.73 mm. Within 10 mm of the PB, however, dWT did not change significantly. When the aorta was mechanically constricted, peak systolic pressure increased approx.50%. Wall thickening decreased to the same relative degree in nonischemic muscle less than 10 mm and more than 10 mm from the perfusion boundary. By fitting sigmoid curves to the data, they estimated the extent of nonischemic dysfunction. It averaged 26 +/- 6/sup 0/ (6-8 mm of endocardial circumference) during coronary occlusion alone and it was not significantly different (29 +/- 11/sup 0/) after aortic constriction. Thus elevated afterload affects nonischemic myocardium uniformly and does not increase the size ore relative severity of the functional border zone.

• Research Organization: Univ. of Michigan, Ann Arbor
• OSTI ID: 5877867
• Journal Information: Am. J. Physiol.; (United States), Vol. 252:4
• Country of Publication: United States
• Language: English

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DYNAMIC FUNCTION STUDIES
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TRACER TECHNIQUES
MYOCARDIUM
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AORTA
CERIUM 141
CHROMIUM 51
DOGS
NIOBIUM 95
PERFUSED TISSUES
RUBIDIUM 103
SCANDIUM 46
TIN 113
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CHROMIUM ISOTOPES
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ELECTRON CAPTURE RADIOISOTOPES
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HEART
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ISOMERIC TRANSITION ISOTOPES
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MAMMALS
MINUTES LIVING RADIOISOTOPES
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RUBIDIUM ISOTOPES
SCANDIUM ISOTOPES
SECONDS LIVING RADIOISOTOPES
TIN ISOTOPES
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