What is the clinical evidence from this study?

Study design: Other. Population: Healthy (animal model) (n=12). Intervention: Ryanodine vs. Baseline (before ryanodine). Primary outcome: Mechanical restitution time constant (p=< 0.05).

What question did this study set out to answer?

This study aims to explore how ryanodine influences calcium release from the sarcoplasmic reticulum and its effects on heart function in dogs.

December 1, 1998Cardiovascular ResearchOpen Access

Ryanodine and the left ventricular force–interval and relaxation–interval relations in closed-chest dogs: insights on calcium handling

Q: What are the key findings of this study?

Ryanodine accelerated mechanical restitution (time constant 60.3 vs 81.7 ms, p<0.05) and slowed early relaxation restitution (65.5 vs 36.8 ms, p<0.05) in intact dogs.

Q: What question did this study set out to answer?

This study aims to explore how ryanodine influences calcium release from the sarcoplasmic reticulum and its effects on heart function in dogs.

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Key result

Ryanodine accelerated mechanical restitution (time constant 60.3 vs 81.7 ms, p<0.05) and slowed early relaxation restitution (65.5 vs 36.8 ms, p<0.05) in intact dogs.

Why the study?

Does ryanodine alter mechanical restitution, relaxation restitution, and force-frequency response in closed-chest dogs?

Population

12 dogs instrumented with left ventricular manometers and piezoelectric dimension crystals

Comparison

Ryanodine (4 micrograms/kg intravenously) vs Baseline (before ryanodine administration)

Design

Preclinical

Authors

SPSumanth D. PrabhuHeart Failure & Transplant

Discussion

Member takes

Implication

Highlights SR calcium handling in canine restitution; leaves open translation to human ventricular mechanics.

Key Points

This study aims to explore how ryanodine influences calcium release from the sarcoplasmic reticulum and its effects on heart function in dogs.
Twelve dogs were instrumented to measure left ventricular function.
After administering ryanodine at 4 micrograms/kg intravenously, various cardiac responses were assessed.
End-systolic elastance and relaxation restitution were measured at different heart rates and intervals.
Ryanodine accelerated mechanical restitution (time constant 60.3 ms vs. 81.7 ms, p < 0.05).
It reduced maximal contractile response (107.5% vs. 122.1%, p < 0.05).
Ryanodine slowed early relaxation restitution (time constant 65.5 ms vs. 36.8 ms, p < 0.05), but did not affect late relaxation restitution.

Structured PICO

Does ryanodine alter mechanical restitution, relaxation restitution, and force-frequency response in closed-chest dogs?

Population

12 dogs instrumented with left ventricular manometers and piezoelectric dimension crystals studied before and after ryanodine administration.

Intervention

Ryanodine (4 micrograms/kg intravenously)

Comparator

Baseline (before ryanodine administration)

Outcome

Mechanical restitution, relaxation restitution, and force-frequency response (end-systolic elastance)surrogate

Main Result

Absolute Event Rate: 60.3% vs 81.7%

p-value: p=< 0.05

In intact dogs, sarcoplasmic reticulum calcium handling is a primary determinant of mechanical and early relaxation restitution, while sarcolemmal calcium influx drives frequency potentiation.

Cite This Study

Sumanth D. Prabhu (1998) studied Healthy (animal model) (n=12). Ryanodine vs. Baseline (before ryanodine) was evaluated on Mechanical restitution time constant (p=< 0.05). Ryanodine accelerated mechanical restitution (time constant 60.3 vs 81.7 ms, p<0.05) and slowed early relaxation restitution (65.5 vs 36.8 ms, p<0.05) in intact dogs.

synapsesocial.com/papers/6a22e6b34a4edab11060658c https://doi.org/10.1016/s0008-6363(98)00201-6

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Ryanodine and the left ventricular force–interval and relaxation–interval relations in closed-chest dogs: insights on calcium handling

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Ryanodine and the left ventricular force–interval and relaxation–interval relations in closed-chest dogs: insights on calcium handling

Discussion

Member takes

Implication

Key Points

Structured PICO

Main Result

Cite This Study

Also Consider

Also Consider