AJP - Heart and Circulatory Physiology, Vol 241, Issue 1 95-103, Copyright © 1981 by American Physiological Society
Acute and chronic changes after aortic valve damage in the intact dog
I. Belenkie and A. Rademaker
Acute aortic regurgitation was produced under anesthesia in 11 closed-chest
dogs previously instrumented with ultrasound transducers. The immediate
responses included increases in end-diastolic diameter (EDD), fractional
shortening (FS), heart rate, left ventricular end-diastolic pressure
(LVEDP), and pulmonary capillary wedge pressure (PCWP), the latter being
transient as was a decrease in left ventricular peak systolic pressure
(LVSP). End-systolic diameter (ESD) did not change. The grouped data
suggest that no further changes occurred following the initial responses
except in PCWP and LVSP. The data from individual dogs showed that there
was a tendency for EDP, LVEDP, and PCWP to return toward control values
after the initial increases in those dogs in which the heart rate increased
after valve damage. This suggests that there were ongoing compensatory
adjustments after the initial responses in this subgroup. Twelve dogs were
followed chronically in the intact conscious state with echocardiographic
measurements after acute aortic valve damage. EDD and ESD increased rapidly
for about 80 days after which EDD increased slowly, whereas ESD showed no
further change. Wall thickness and FS did not change throughout the period
of study, suggesting that increasing wall thickness may be a relatively
late change and that it may be related to the level of myocardial
compensation.
