Myocardial fiber architecture and left ventricular function

Article type: Research Article

Authors: Ingels Jr, Neil B.

Affiliations: Department of Cardiovascular Physiology and Biophysics, Research Institute, Palo Alto Medical Foundation, 860 Bryant Street, Palo Alto, California 94301, USA. Tel.: +1 415 853 4834; Fax: +1 415 324 2665; E-mail: [email protected]

Abstract: This paper develops several working hypotheses regarding the coupling between myocardial fiber architecture and left ventricular function. First, the coupling between spiral myocardial fibers and left ventricular torsional deformation and ejection fraction is examined. A proposal is then made to account for the observed change in orientation of myocardial fibers from a right hand helix in the subendocardium, through circumferential fibers in the midwall, to a left hand helix in the subepicardium in terms of a requirement for generating physiological values of both ejection fraction and pressure as well as equilibration of transmural fiber work. Finally, a pumping hypothesis is developed linking the contraction of each transmural layer of fibers to one another via collagen struts and weaves, with the resulting force transmitted to the epicardium and thence, by means of hydraulic forces associated with the constant volume property of the LV wall, to the endocardium to reduce the volume of the left ventricular chamber.

DOI: 10.3233/THC-1997-51-205

Journal: Technology and Health Care, vol. 5, no. 1-2, pp. 45-52, 1997