Aortic pressure reduction redistributes transmural blood flow in dog left ventricle

Journal Article · Mon Feb 01 04:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6945597

Smolich, J J; Weissberg, P L; Broughton, A; Korner, P I ^[1]

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1. Baker Medical Research Institute, Melbourne (Australia)

The authors studied the effect of graded aortic blood pressure reduction on left ventricular (LV) blood flow in anesthetized, autonomically blocked, open-chest dogs at constant heart rate and mean left atrial pressure. Aortic diastolic pressure (ADP) was lowered from rest to 90, 75, and 60 mmHg with an arteriovenous fistula. Global and regional LV blood flow was measured with radioactive microspheres. Mean LV blood flow fell stepwise from 145 ml {center dot} min{sup {minus}1} {center dot} 100 g{sup {minus}1} at rest to 116 ml {center dot} min{sup {minus}1} {center dot} 100 g{sup {minus}1} at ADP of 60 mmHg, whereas the endocardial-to-epicardial flow ratio decreased from 1.20 to 084. The transmural redistribution of LV blood flow was not accompanied by increases in LV oxygen extraction, depression of LV contractility, LV dilatation or LV electrical dysfunction and also occurred in the presence of considerable coronary vasodilator flow reserve. Electrical evidence of subendocardial ischemia appeared at ADP of 32 mmHg and an endocardial-to-epicardial flow ratio of 0.41 in a subgroup of animals. They conclude that the redistribution of LV flow during moderate aortic pressure reduction was an appropriate physiological adjustment to uneven transmural alterations in regional LV wall stress and that it preceded a more pronounced redistribution evident with myocardial ischemia.

• OSTI ID: 6945597
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 254:2; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

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551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
AORTA
ARTERIES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD FLOW
BLOOD PRESSURE
BLOOD VESSELS
BODY
CALCIUM COMPOUNDS
CARDIOVASCULAR DISEASES
CARDIOVASCULAR SYSTEM
CERIUM 141
CERIUM ISOTOPES
CHROMIUM 51
CHROMIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
DISEASES
DOGS
ELECTROMAGNETIC RADIATION
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
GAMMA RADIATION
HEART
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISCHEMIA
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MICROSPHERES
MINUTES LIVING RADIOISOTOPES
MUSCLES
MYOCARDIUM
NIOBIUM 95
NIOBIUM ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANS
PHYSIOLOGY
RADIATIONS
RADIOASSAY
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
SCANDIUM 46
SCANDIUM ISOTOPES
SECONDS LIVING RADIOISO
STRONTIUM 85
STRONTIUM ISOTOPES
TIN 113
TIN ISOTOPES
VASCULAR DISEASES
VASODILATION
VERTEBRATES