What question did this study set out to answer?

To determine how coronary muscarinic receptor activation influences the distribution of transmural blood flow across the left ventricular wall.

June 1, 1981AJP Heart and Circulatory Physiology

Transmural distribution of blood flow during activation of coronary muscarinic receptors

Q: What is the clinical evidence from this study?

Study design: Other. Intervention: Intracoronary infusions of acetylcholine vs. Adenosine (54.4 micrograms/min) and baseline. Primary outcome: Subendocardial-subepicardial blood flow ratio (endo/epi).

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Key result

Intracoronary infusions of acetylcholine increased the subendocardial-subepicardial blood flow ratio from 1.07 to 1.32 and 1.57 at doses of 5.0 and 10.7 micrograms/min, respectively.

Why the study?

Does intracoronary acetylcholine alter transmural blood flow distribution in anesthetized open-chest dogs?

Population

Anesthetized open-chest dogs

Comparison

Intracoronary infusions of acetylcholine… vs Baseline and intracoronary administration of…

Design

Preclinical

Authors

GGG. J. GrossHospital for Sick Children JBJ. BuckKatharinenhospital DWDavid C. WarltierGeneral Cardiology

Discussion

Member takes

Implication

Suggests acetylcholine augments subendocardial perfusion; leaves open clinical translation in coronary disease.

Key Points

To determine how coronary muscarinic receptor activation influences the distribution of transmural blood flow across the left ventricular wall.
Evaluated anesthetized, open-chest dogs pretreated with intravenous sotalol (2.0 mg/kg) to block beta-adrenergic receptors.
Measured tissue blood flow across subepicardial, midmyocardial, and subendocardial layers using radioactive microspheres during intracoronary infusions of acetylcholine and adenosine.
Assessed changes in hemodynamic parameters and tested muscarinic receptor specificity using atropine blockade.
Intracoronary acetylcholine (5.0 and 10.7 µg/min) increased the subendocardial-to-subepicardial flow ratio in a dose-dependent manner from 1.07 to 1.32 and 1.57, respectively, driven by a larger vascular resistance decrease in the subendocardium.
Intracoronary adenosine (54.4 µg/min) produced equivalent total coronary vasodilation but caused no change in the subendocardial-to-subepicardial flow ratio.
Atropine selectively blocked acetylcholine-induced vasodilation without altering adenosine-induced dilation, with neither drug modifying heart rate, ventricular pressure, or myocardial contractility.

Structured PICO

Does intracoronary acetylcholine alter transmural blood flow distribution in anesthetized open-chest dogs?

Population

Anesthetized open-chest dogs studied to determine the role of coronary muscarinic receptors in transmural blood flow distribution.

Intervention

Intracoronary infusions of acetylcholine (5.0 and 10.7 micrograms/min) following beta-blockade with sotalol (2.0 mg/kg iv)

Comparator

Baseline and intracoronary administration of adenosine (54.4 micrograms/min)

Outcome

Transmural blood flow distribution (subendocardial-subepicardial blood flow ratio, endo/epi) determined with radioactive microspheressurrogate

Activation of muscarinic coronary vasodilator receptors redistributes blood flow preferentially to the subendocardium independent of cardiac mechanical influences.

Cite This Study

Gross et al. (1981) studied this question. Intracoronary infusions of acetylcholine vs. Adenosine (54.4 micrograms/min) and baseline was evaluated on Subendocardial-subepicardial blood flow ratio (endo/epi). Intracoronary infusions of acetylcholine increased the subendocardial-subepicardial blood flow ratio from 1.07 to 1.32 and 1.57 at doses of 5.0 and 10.7 micrograms/min, respectively.

synapsesocial.com/papers/6a6dda78ce524a4339c2d62d https://doi.org/10.1152/ajpheart.1981.240.6.h941

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Transmural distribution of blood flow during activation of coronary muscarinic receptors

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Transmural distribution of blood flow during activation of coronary muscarinic receptors

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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