NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Cover of Regulation of Cardiac Contractility

Regulation of Cardiac Contractility

.

Department of Physiology and Biophysics, University of Illinois at Chicago, College of Medicine, Chicago, IL
San Rafael (CA): Morgan & Claypool Life Sciences; .

ABSTRACT

Contractility describes the relative ability of the heart to eject a stroke volume (SV) at a given prevailing afterload (arterial pressure) and preload (end-diastolic volume; EDV). Various measures of contractility are related to the fraction as the SV/EDV or the ejection fraction, and the dynamics of ejection as determined from maximum pressure rise in the ventricles or arteries or from aortic flow velocities determined by echocardiography. At the cellular level, the ultimate determinant of contractility is the relative tension generation and shortening capability of the molecular motors (myosin cross-bridges) of the sarcomeres as determined by the rates and extent of Ca activation, the turnover kinetics of the cross-bridges, and the relative Ca responsiveness of the sarcomeres. Engagement of the regulatory signaling cascades controlling contractility occurs with occupancy and signal transduction by receptors for neurohumors of the autonomic nervous system as well as growth and stress signaling pathways. Contractility is also determined by the prevailing conditions of pH, temperature, and redox state. Short-term control of contractility is fully expressed during exercise. In long-term responses to stresses on the heart, contractility is modified by cellular remodeling and altered signaling that may compensate for a time but which ultimately may fail, leading to disorders.

Contents

Copyright © 2011 by Morgan & Claypool Life Sciences.
Bookshelf ID: NBK54078PMID: 21634071DOI: 10.4199/C00030ED1V01Y201104ISP018
PubReader format: click here to try

Views

Related information

Related citations in PubMed

See reviews...See all...

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...