What is the clinical evidence from this study?

Population: Myocardial contractility in isolated rabbit hearts (n=38). Intervention: Guanethidine or reserpine vs. Untreated. Primary outcome: Active tension developed by the ventricles as a function of stretch.

What question did this study set out to answer?

This research investigates how catecholamine depletion affects myocardial contractility in isolated rabbit hearts.

July 1, 1964Experimental Biology and Medicine

Effect of Catecholamine Depletion on an Index of Myocardial Contractility in Isolated Rabbit Hearts.

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Key result

Catecholamine depletion (70 to 94% reduction) using guanethidine or reserpine did not necessarily result in severe impairment of myocardial contractility in isolated rabbit hearts.

Why the study?

Does catecholamine depletion via guanethidine or reserpine reduce myocardial contractility in isolated rabbit hearts?

Population

Isolated hearts from 38 rabbits

Comparison

Pretreatment with guanethidine or reserpine to… vs Untreated isolated rabbit hearts

Design

Preclinical

Authors

RMR.A. MaxwellUniversity of Vermont JKJason KelleyUniversity of Vermont EEE. T. EckhardtUniversity of Vermont

Discussion

Member takes

Implication

May inform dosing in future sympathetic blockade studies; leaves open translation to human ventricular mechanics.

Key Points

This research investigates how catecholamine depletion affects myocardial contractility in isolated rabbit hearts.
Isolated rabbit hearts were evaluated under varying doses of guanethidine and reserpine.
Hearts were subjected to graded stretching to measure active tension development.
Measurements were taken from untreated rabbits and those pretreated with guanethidine and reserpine.
Guanethidine (10 mg/kg) led to a 70-94% reduction in catecholamine content while depressing tension development.
Higher doses of guanethidine and reserpine did not significantly impair contractility.
Severe reduction in catecholamine levels did not cause a corresponding decrease in contractility.

Structured PICO

Does catecholamine depletion via guanethidine or reserpine reduce myocardial contractility in isolated rabbit hearts?

Population

38 isolated rabbit hearts (11 untreated, 27 pretreated with guanethidine or reserpine) subjected to graded stretch to measure active tension development.

Intervention

Pretreatment with guanethidine (10 mg/kg or 20 mg/kg) or reserpine (3 mg/kg) to induce catecholamine depletion

Comparator

Untreated isolated rabbit hearts

Outcome

Active tension developed by the ventricles as a function of stretch (index of myocardial contractility)surrogate

Drastic reduction in catecholamine content of the left ventricle does not necessarily result in severe impairment of its contractility in isolated rabbit hearts.

Cite This Study

Maxwell et al. (1964) studied Myocardial contractility in isolated rabbit hearts (n=38). Guanethidine or reserpine vs. Untreated was evaluated on Active tension developed by the ventricles as a function of stretch. Catecholamine depletion (70 to 94% reduction) using guanethidine or reserpine did not necessarily result in severe impairment of myocardial contractility in isolated rabbit hearts.

synapsesocial.com/papers/6a6a2b8f327391d1bb1a836d https://doi.org/10.3181/00379727-116-29340

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Effect of Catecholamine Depletion on an Index of Myocardial Contractility in Isolated Rabbit Hearts.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Effect of Catecholamine Depletion on an Index of Myocardial Contractility in Isolated Rabbit Hearts.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider