What question did this study set out to answer?

To determine whether variations in the mechanical work of the heart influence total coronary blood flow and vice versa under controlled hemodynamic conditions.

February 1, 1961American Journal of Physiology-Legacy Content

Relations between coronary flow and work of the heart

Q: What is the clinical evidence from this study?

Study design: Other. Population: Coronary flow and heart work. Intervention: Variation of work performed and aortic pressure vs. Constant working conditions. Primary outcome: Changes in coronary flow and pressure-flow relationships.

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Key result

Changes in the work performed by dog hearts do not result in changes of coronary flow when stimulation frequency and aortic pressure are constant, indicating a wide margin of safety in oxygen supply.

Why the study?

Does varying the work of the heart affect coronary flow in isolated perfused dog hearts?

Population

Dog hearts, perfused via the aorta by a donor dog

Comparison

Variation of the amount of work performed by the… vs Constant frequency of stimulation and aortic…

Design

Preclinical

Authors

ARA. RosenbluethHarvard University JAJ AlanísMexican Social Security Institute RRR. RubioInstituto Nacional de Cardiologia

Discussion

Member takes

Implication

Indicates substantial coronary reserve in controlled settings; leaves open translation to human autoregulation and clinical relevance.

Key Points

To determine whether variations in the mechanical work of the heart influence total coronary blood flow and vice versa under controlled hemodynamic conditions.
Measured mean total coronary flow in canine hearts perfused via the aorta by a donor dog.
Varied cardiac work output across wide ranges while selectively modulating aortic perfusion pressure and keeping pacing rate constant.
Variations in cardiac work output did not cause changes in coronary blood flow when heart stimulation rate and aortic pressure remained constant.
Modulations of coronary flow produced no variations in cardiac work output under stable working conditions.
Cardiac work did not alter coronary pressure-flow dynamics, demonstrating that hearts can markedly elevate work output without requiring an increase in coronary blood flow.

Structured PICO

Does varying the work of the heart affect coronary flow in isolated perfused dog hearts?

Population

Experimental study on dog hearts perfused via the aorta by a donor dog to assess relations between coronary flow and work of the heart.

Intervention

Variation of the amount of work performed by the recipient heart and variation of aortic pressure

Comparator

Constant frequency of stimulation and aortic pressure; constant working conditions

Outcome

Changes in coronary flow and pressure-flow relationshipssurrogate

The heart can increase its work significantly without requiring an increase in coronary flow, indicating a wide margin of safety in oxygen supply to the ventricle under adequate circulation.

Cite This Study

Rosenblueth et al. (1961) studied Coronary flow and heart work. Variation of work performed and aortic pressure vs. Constant working conditions was evaluated on Changes in coronary flow and pressure-flow relationships. Changes in the work performed by dog hearts do not result in changes of coronary flow when stimulation frequency and aortic pressure are constant, indicating a wide margin of safety in oxygen supply.

synapsesocial.com/papers/6a9ffde5585a22130a62a110 https://doi.org/10.1152/ajplegacy.1961.200.2.243

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Relations between coronary flow and work of the heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Relations between coronary flow and work of the heart

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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