What question did this study set out to answer?

This research aims to understand how abrupt load changes affect the shortening dynamics of heart muscle during isotonic contractions.

July 1, 1971The Journal of PhysiologyOpen Access

Effects of abrupt load alterations on force—velocity—length and time relations during isotonic contractions of heart muscle: load clamping

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Population

Cat papillary muscles

Comparison

Abrupt alterations in load during the course of… vs Load imposed before stimulation

Design

Preclinical

Authors

DBD L BrutsaertBrigham and Women's Hospital VCVictor ClaesUniversity of Antwerp ESEdmund H. SonnenblickUniversity of Parma

Discussion

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Implication

Should not alter clinical management; leaves open whether length-dependent velocity governs human myocardial contraction.

Key Points

This research aims to understand how abrupt load changes affect the shortening dynamics of heart muscle during isotonic contractions.
Load clamping was applied to cat papillary muscles during isotonic shortening from onset to peak shortening.
Velocity of shortening was analyzed in relation to instantaneous length rather than the history of tension changes.
Evaluated the independence of force-velocity-length relations from time during the contraction process.
The velocity of shortening is solely determined by instantaneous length, not the sequence of length or tension changes.
Force-velocity-length relations remain consistent from the onset of shortening to just before peak shortening.
Heart muscle maintains awareness of total load during the shortening process.

Structured PICO

Population

Cat papillary muscles

Intervention

Abrupt alterations in load (load-clamping) during the course of isotonic shortening

Comparator

Load imposed before stimulation

Outcome

Force-velocity-length and time relationssurrogate

This preclinical study demonstrates that in heart muscle, the velocity of shortening is determined solely by instantaneous length for a given load, suggesting a steady state of active state intensity during contraction.

Cite This Study

Brutsaert et al. (1971) studied this question.

synapsesocial.com/papers/6a2147d2f69db56553c3d485 https://doi.org/10.1113/jphysiol.1971.sp009527

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Effects of abrupt load alterations on force—velocity—length and time relations during isotonic contractions of heart muscle: load clamping

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Effects of abrupt load alterations on force—velocity—length and time relations during isotonic contractions of heart muscle: load clamping

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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