|
|
||||||||
Journal of Applied Physiology, Vol 38, Issue 6 1110-1116, Copyright © 1975 by American Physiological Society
ARTICLES |
H. L. Stone
The relationship between heart rate and left atrial end-diastolic diameter (LAEDD) and left atrial systolic shortening (LASS) was investigated in 12 conscious dogs. Atrial pacing, vagal blockade, isoproterenol, and beta-adrenergic blockade were used to change heart rate and the inotropic state of the atrium. LAEDD decreased linearly as heart rate increased. LAEDD averaged 33.0 mm (+/- 0.6 mm SEM) and decreased by 3.2 mm (+/- 0.4 mm SEM) with a change in heart rate of 50 beats/min. The ratio of LASS/LAEDD decreased as LAEDD decreased with increasing heart rate, but there was less of a reduction in the ratio at the extreme levels of LAEDD change with isoproterenol and vagal blockade. Propranolol reduced LASS at any LAEDD. At lower heart rates the reduction of LASS with pacing could be corrected by returning LAEDD to near control levels with a rapid infusion of fluid. It is concluded that LASS is primarily dependent on LAEDD and the inotropic state of the atrium. At higher heart rates, though, some effect of frequency can be observed. Isoproterenol and vagal blockade (increased contractile state) reduced the dependence of LASS on LAEDD.
This article has been cited by other articles:
![]() |
T. Konishi, T. Ichikawa, N. Isaka, M. Sugawa, and T. Nakano Assessment of Mitral Regurgitation Using Gated Radionuclide Ventriculography: Analysis of Left Atrial Time Activity Curve Angiology, May 1, 1990; 41(5): 387 - 393. [Abstract] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |