Circulation, Vol 51, 718-722, Copyright © 1975 by American Heart Association
BL Lloyd and RR Taylor
The effect of the shock state on myocardial digoxin uptake and plasma
digoxin levels was examined in unanesthetized dogs following hemorrhage.
Five minutes after intravenous administration of tritiated digoxin the
myocardial digoxin content in animals with shock was greater than in normal
animals in both left ventricle (LV) (165 plus or minus 15 (SD) ng/g vs 130
plus or minus 26 ng/g, P smaller than 0.02 and right ventricle (RV) (142
plus or minus 13 ng/g vs 111 plus or minus 22 ng/g. P smaller than 0.02) as
was the plasma digoxin concentration (61.6 plus or minus 11.8 ng/ml vs 44.3
plus or minus 4.6 ng/ml, P smaller than 0.02). After one hour, in another
group of dogs, the difference in myocardial concentration of digoxin
between test and normal groups was even greater (LV: 213 plus or minus 26
ng/g vs 133 plus or minus 13 ng/g, P smaller than 0.001; RV: 171 plus or
minus 9 ng/g vs 111 plus or minus 8 ng/g. P smaller than 0.001) despite
lower plasma digoxin concentration in the test group (12.9 plus or minus
2.9 ng/ml vs 17.3 plus or minus 2.5 ng/ml, P smaller than 0.05). Diminished
peripheral blood flow, peripheral digoxin delivery and uptake were probably
responsible for the early difference in plasma digoxin levels. Resultant
greater plasma concentrations of digoxin presented to the myocardium in the
early phase, coupled with relative preservation of myocardial blood flow,
may explain the greater myocardial uptake in animals with shock although
myocardial mechanical factors may also be implicated. Augmented uptake of
digoxin by the myocardium in canine hemorrhagic shock may be relevant to
the altered susceptibility to glycoside action in clinical shock syndromes.
ARTICLES
Augmentation of myocardial digoxin concentration in hemorrhagic shock
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