78 
CARDIAC MODELS 
CHRONIC BIVENTRICULAR BYPASS 
VENTRICULAR FIBRILLATION 
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A Y\ A' A A A 
f f ' \ r r f 
Calf 309 
NSR 
VF 
Aorta 
156/120 (132) 
150/120 (130) 
Pulmonary Artery 
26/12 (18) 
30/12 (21) 
Figure 13. — Pressure recordings obtained during a con- 
trol state (left) and during induction of ventricular 
fibrillation (center, right) . Ecg = external electro- 
cardiogram. VF — point of electrical induction of 
fibrillation. Ao, PA, LVAD = aorta, pulmonary ar- 
tery and left ventricular pump air drive pressures, 
calibrated by matching asterisks. Right and left ven- 
tricular, and right ventricular pump air drive pres- 
sures not shown. NSR — normal sinus rhythm. Mean 
arterial pressures appear in parentheses. 
coronary occluder technique for use in inducing 
acute, reversible ventricular failure, rather than 
the chronic state which he described. The Oc- 
cluder consists of a silastic balloon attached to a 
dacron-reinforced belt, and bonded to a long, 
thin silastic tube. 
At the time of blood-pump implantation, the 
occluder was fixed around the main left coro- 
nary artery, uninflated, and the silastic tube 
brought out through the chest wall. Five calves 
were studied on 8 occasions : 7 times by cardiac 
catheterization and once awake, in a stall. In 
the latter instance, only the Ecg was recorded, 
prior to cardiac catheterization. In all other 
instances, complete cardiac catheterizations 
were performed: control state recordings were 
followed by manual inflation of the coronary oc- 
cluder with COo (or saline-Renovist mixture) 
in a syringe. Repeat pressures and angiograms 
were recorded after the LV end-diastolic pres- 
sure (LVedp) stabilized at the desired level. 
Following such hemodynamic studies (15 to 30 
minutes continuous failure), the failure was re- 
versed by deflation of the balloon, and the Ecg 
and pressures returned to normal (Figure 4). 
In all but one instance, the calves were returned, 
awake, to the animal farm. In the one instance, 
it proved impossible to deflate the balloon in 
any manner except by further inflation and rup- 
ture. Ventricular fibrillation followed shortly, 
and the animal, inadequately supported by the 
LV blood pump alone, died after 45 minutes. 
LV Failure— Chronic: Strontium-90 
Irreversible damage is done to myocardium 
by high-dose radiation therapy: a myocardo- 
pathy with diffuse, severe fibrosis and chronic 
failure results. Theoretically, this effect could 
be reproduced experimentally by direct, specific 
radiation of myocardium without involvement 
of surrounding structures. 
For this purpose, a 300-millicurie source of 
Strontium-90 was encapsulated and mounted at 
the tip of a #8 French catheter. The beta-radia- 
tion dose rate at the active surface was 10,000 
rad/hr. 
A 36 kilogram dog was anesthetized with so- 
dium pentobarbital and placed on a Harvard 
respirator with an endotracheal tube. The spe- 
cial catheter was passed from the right femoral 
artery, retrograde, to the LV where multiple 
sites were selected fluoroscopically for 20 minute 
periods of direct beta radiation. At the conclu- 
sion of the study, the dog returned to the animal 
farm with no immediate change in LV pres- 
sures (110/4-8 mmHg) or Ecg. No change 
occurred during the subsequent 3 months. The 
animal was sacrificed for pathological examina- 
tion at the end of that time. 
LV Failure— Chronic: Cobaltous Chloride 
(CoCI • 6H2O) 
An entire issue of the Canadian Medical 
Association Journal in 1967 was devoted to 
an examination of the syndrome called Quebec 
Beer-Drinker's Cardiomyopathy, including a 
review and discussion of etiology. Experi- 
mental cardiomyopathy was produced by Morin 
in the rabbit in 1968.-" Since this latter purpose 
was accomplished without additional alcohol, 
an experiment was designed to create cobalt 
cardiomyopathy in rats and dogs, prior to its 
use in calves. 
