Adaptive control of cardiac contraction to changes in loading: From theory of sarcomere dynamics to whole-heart function

Moran Yadid, Gali Sela, Daria Amiad Pavlov, Amir Landesberg

Research output: Contribution to journalReview articlepeer-review

13 Scopus citations

Abstract

The heart accommodates to rapid changes in demands. This review elucidates the adaptive control of cardiac function by loading conditions, and integrates the sarcomeric control of contraction (SCC) with isolated trabeculae and in vivo whole-heart studies. The SCC includes two feedback mechanisms: (1) cooperativity that regulates cross-bridge (XB) recruitment and the force-length relationship, and (2) mechanical feedback, whereby the filament-sliding velocity determines the XB-weakening rate and the force-velocity relationship. An isolated rat trabeculae study tested the suggested mechanisms during sarcomeric lengthening. The observations indicate that lengthening decreases the XB-weakening rate in a velocity-dependent manner, congruent with the suggested hypothesis and in contrast to alternative theories. A whole-heart level study in sheep reveals the existence of a preload-independent linear relationship between the external work (EW) and pressure-time integral during transient vena cava occlusions, for any given afterload, and not just at isovolumic contractions. The slope of this relationship decreases as the afterload increases. These findings highlight the mechanisms underlying the pressure (Frank's phenomenon) and EW (Starling's phenomenon) generation and the roles that the preload and afterload play. The theoretical, isolated fibers and whole-heart studies provide complementary information that strengthens our understanding of cardiac function from the top-down and bottom-up.

Original languageEnglish
Pages (from-to)49-60
Number of pages12
JournalPflugers Archiv European Journal of Physiology
Volume462
Issue number1
DOIs
StatePublished - Jul 2011
Externally publishedYes

Bibliographical note

Funding Information:
This study was supported by the fund for the promotion of research at the Technion, by grants from the United States–Israel Binational Science Foundation (No. 2003399), and the Israel Science Foundation (No. 1256/06).

Funding

This study was supported by the fund for the promotion of research at the Technion, by grants from the United States–Israel Binational Science Foundation (No. 2003399), and the Israel Science Foundation (No. 1256/06).

FundersFunder number
United States-Israel Binational Science Foundation2003399
Israel Science Foundation1256/06
Technion-Israel Institute of Technology

    Keywords

    • Cardiac mechanics
    • Contractility
    • Cooperativity
    • Cross-bridge dynamics
    • Economy
    • Efficiency
    • Excitation-contraction coupling
    • Mechanical feedback
    • Sarcomere

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