Abstract
The length-tension diagram, the force-velocity relation, the characteristics of the series elasticity, and the duration of the active state have been studied on the papillary muscle preparation of the cat heart, and on other examples of cardiac muscle. Positive inotropic changes such as the staircase phenomenon and post-extrasystolic potentiation occur without lengthening, but frequently with shortening, of the duration of the active state. They are accompanied by an increased velocity of contraction, and may be caused either by an intensification of the active state or by an alteration of the force-velocity characteristics of the contractile component. The changes in the force-velocity relation point to an adaptation of the velocity-efficiency relation in dependence on the frequency of contraction.
Full Text
The Full Text of this article is available as a PDF (927.2 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BURTON A. C. The importance of the shape and size of the heart. Am Heart J. 1957 Dec;54(6):801–810. doi: 10.1016/0002-8703(57)90186-2. [DOI] [PubMed] [Google Scholar]
- GOFFART M., RITCHIE J. M. The effect of adrenaline on the contraction of mammalian skeletal muscle. J Physiol. 1952 Mar;116(3):357–371. doi: 10.1113/jphysiol.1952.sp004710. [DOI] [PMC free article] [PubMed] [Google Scholar]
- NIEDERGERKE R. The staircase phenomenon and the action of calcium on the heart. J Physiol. 1956 Dec 28;134(3):569–583. doi: 10.1113/jphysiol.1956.sp005666. [DOI] [PMC free article] [PubMed] [Google Scholar]
- RITCHIE J. M. The effect of nitrate on the active state of muscle. J Physiol. 1954 Oct 28;126(1):155–168. doi: 10.1113/jphysiol.1954.sp005200. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rushton W. A. Excitable substances in the nerve-muscle complex. J Physiol. 1930 Dec 4;70(4):317–337. doi: 10.1113/jphysiol.1930.sp002698. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WILKIE D. R. Measurement of the series elastic component at various times during a single muscle twitch. J Physiol. 1956 Dec 28;134(3):527–530. doi: 10.1113/jphysiol.1956.sp005662. [DOI] [PMC free article] [PubMed] [Google Scholar]
- WILKIE D. R. The mechanical properties of muscle. Br Med Bull. 1956 Sep;12(3):177–182. doi: 10.1093/oxfordjournals.bmb.a069546. [DOI] [PubMed] [Google Scholar]