Coronary vasodilator reserve persists despite tachycardia and myocardial ischemia

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · American Journal of Physiology; (USA)

OSTI ID:5036484

Bristow, J D; McFalls, E O; Anselone, C G; Pantely, G A ^[1]

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1. Oregon Health Sciences Univ., Portland (USA)

During myocardial ischemia, the authors tested whether coronary blood flow measured with radioactive microspheres labeled with {sup 141}Ce, {sup 51}Cr, {sup 103}Ru, and {sup 95}Nb would increase in response to tachycardia thereby employing known coronary flow reserve. The authors instrumented the left anterior descending (LAD) coronary circulation in anesthetized pigs and performed three sets of experiments while coronary pressure was controlled and several heart rate increases were produced. (1) Pacing-induced tachycardia at normal LAD pressure was characterized by increased LAD flow and myocardial oxygen consumption, without production of lactate. (2) Tachycardia at a mean LAD pressure of 38 mmHg was associated with a lower, fixed coronary flow and oxygen consumption. Lactate was produced at all rates and local myocardial function declined progressively. (3) Coronary flow at low LAD pressure doubled during tachycardia when intracoronary adenosine was added. The increase to the subepicardium was >100%, whereas subendocardial flow changed little. There is persistent coronary flow reserve during moderately severe myocardial ischemia, even when metabolic demand is increased by tachycardia. This reserve, however, is predominantly subepicardial.

• OSTI ID: 5036484
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 253:2; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BLOOD FLOW
BODY
CARBOXYLIC ACIDS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR DISEASES
CARDIOVASCULAR SYSTEM
CERIUM 141
CERIUM ISOTOPES
CHEMISTRY
CHROMIUM 51
CHROMIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
DISEASES
DOMESTIC ANIMALS
DRUGS
DYNAMIC FUNCTION STUDIES
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
HEART
HYDROXY ACIDS
INTERMEDIATE MASS NUCLEI
ISCHEMIA
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LACTIC ACID
MAMMALS
METABOLISM
MICROSPHERES
MUSCLES
MYOCARDIUM
NIOBIUM 95
NIOBIUM ISOTOPES
NONMETALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
OXYGEN
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
RUTHENIUM 103
RUTHENIUM ISOTOPES
SWINE
TRACER TECHNIQUES
VASCULAR DISEASES
VASODILATORS
VERTEBRATES