76 
CARDIAC MODELS 
ligations and carbon dioxide infusion for acute 
failure; Strontium-90 radiation, and cobaltous 
chloride intoxication, for chronic failure. The 
two methods which satisfied the criteria of re- 
liability, reproducibility, and low morbidity 
and mortality are the central themes of this 
report: coronary balloon-cuif occlusion for re- 
versible, acute myocardial failure; and coro- 
nary microsphere infusion for irreversible, 
chronic failure. 
METHODS 
Animals, Pumps, and Surgical Implantation 
Calves (65-90 Kg) were selected for all stud- 
ies except the Strontium-90 and cobaltous chlo- 
ride experiments, in which dogs (both) and rats 
(cobaltous chloride) were used. 
The left,^'8 right,» and biventricular 10-12 
pumps have been described previously in detail, 
as have their individual and collective implan- 
tation techniques: '-^11 both pumps are im- 
planted in the left chest, as previously illus- 
trated (see Figure 12). 
Figure 12. — Lateral chest X-ray of calf standing, 
awake, prior to onset of electrically-induced ventric- 
ular fibrillation. Head is to the right. Inflow tubes 
of LV (left and RV (right) pumps are shown below. 
Outflow pump grafts are attached above (on left) 
and right, to the descending aorta and pulmonary 
artery, respectively. 
Briefly, both pumps have a stroke volume of 
100 ml, with a maximum output of 11 L/min. 
The inflow tube is implanted in the left ven- 
tricular (LV) apex or in the right ventricular 
(RV) infundibulum. The outflow grafts of each 
pump are sutured, end-to-side, to the descending 
thoracic aorta, or to the main pulmonary artery. 
The latter is banded proximal to the graft.'' 
Low-profile disc valves guard the inflow and 
outflow ends of the pumping chamber, which 
is polyurethane rubber internally coated with 
a matrix of flocked dacron fibrils. " Pneumatic 
drive lines are connected from the pumps trans- 
cutaneously to an external drive and control 
unit. This unit may be operated at a fixed rate, 
or synchronized with the electrocardiogram 
(Ecg) to counterpulse with the ventricle. It has 
a fail-safe sensor which will switch from a pri- 
mary to a secondary fixed-rate unit in the event 
of primary failure. 
Hemodynamic Studies: Cardiac Catherization 
and Angiography 
Cardiac catherization studies were performed 
under a light halothane anesthesia (0.5-1.0% 
2-bromo-2-chloro-l :1 :l-trifluoroethane) admin- 
istered through an endotracheal tube. Respira- 
tions were supported by a Bennett positive pres- 
sure ventilator, and a nasogastric decompression 
tube inserted. The right jugular vein and carotid 
artery were exposed for all studies, and car- 
diac catheters (United States Catheter and In- 
strument Corporation) positioned in RV and 
pulmonary artery (PA), and in LV and Aorta 
(Ao). The latter catheter was positioned in the 
main left coronary artery for induction of micro- 
sphere or carbon dioxide (COo) failure. An ad- 
ditional Statham P-866 or SF-1 catheter was 
positioned in the LV body for high fidelity pres- 
sure recordings. The standard protocol included 
baseline measurements of pressures, flows, and 
heart rates with pump(s) on and off, synchro- 
nous and asynchronous with the Ecg, and re- 
cordings of LV (or RV) biplane angiograms. 
The latter were recorded at 6 frames per sec- 
ond during injection of Renovist (sodium and 
meglumine diatrazoates) , using an Elema- 
Schonander roll-film changer. Following this, 
myocardial failure would be induced by the 
