Control of cardiac function: an overview

Chaytor, Andrew

doi:10.1016/j.mpaic.2009.05.005

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Volume 10, Issue 8 , Pages 370-372, August 2009

Control of cardiac function: an overview

Andrew Chaytor PhD is a Lecturer at the School of Medicine and Health, Durham University, UK. He has a PhD from the School of Medicine, Cardiff University, UK, and has worked as a British Heart Foundation Research Fellow at the Wales Heart Research Institute, Cardiff, and at the Sunderland School of Pharmacy, UK. His research interests include mechanisms controlling vascular tone and the role of electrical signalling between endothelial and muscle cells in the cardiovascular system. Conflicts of interest: none declared

Abstract

Cardiac output is the volume of blood ejected per ventricle per minute and is a measure of cardiac performance. It is the product of the strength of ventricular contraction, which determines how much blood is ejected (stroke volume), and the heart rate. Factors that control the force of contraction include the degree of myocardial stretch or Starling's Law, which is determined by venous return, and also the amount of cytosolic calcium present in muscle cells, which is influenced by sympathetic nerves and circulating catecholamines. Heart rate is also under the influence of the autonomic nervous system and circulating catecholamines. Forces opposing cardiac output include arterial blood pressure and, therefore, peripheral resistance to blood flow.

Keywords: cardiac output, heart rate, inotropes, parasympathetic, Starling's law, stroke volume, sympathetic