AJP - Heart and Circulatory Physiology, Vol 250, Issue 3 378-H388, Copyright © 1986 by American Physiological Society
Regional differences of myocyte hypertrophy and three-dimensional deformation of the heart
T. Kuribayashi, K. Furukawa, H. Katsume, H. Ijichi and Y. Ibata
Cross-sectional area was compared between the latitudinally and
longitudinally oriented muscle fibers of the hypertrophied left ventricle
of the rat heart under aortic banding and isoproterenol infusion. In
addition, end-diastolic three-dimensional deformation of the left ventricle
as expressed by cavity volume and eccentricity was examined in the early
and chronic stages of these treatments. Under aortic banding, myocyte
hypertrophy occurred to a greater extent in the latitudinally oriented
fibers of the midwall layer than in the longitudinal fibers of the inner
and outer layers. Such a regional difference of hypertrophy was not seen
under isoproterenol infusion. At the early stage of aortic banding, the
left ventricle at end diastole was more dilated and spherical, whereas at
the acute stage of isoproterenol infusion, it was more decreased in size
and prolate than that of the controls. The deformation of the left
ventricle at the early stage of aortic banding is considered to cause,
during diastole, axial stretching and increase in tensile stress more on
the latitudinal fibers, leading them to the predominant hypertrophy.
