82 
CARDIAC MODELS 
LV-Ao ASSIST DEVICE -CHRONIC 
LEFT VENTRICULAR FA I LURE -ACUTE (CO2) 
MYOCARDIAL ECG 
Ao PRESSURE 100 
(mmHg) 
LV PRESSURE 0 
PUMP STROKE VOLUME SIGNAL 
CALF #114 
Figure 2.- — Pressure recordings from a calf with a chronically LV blood pump, following induction of mild 
LV failure by coronary CO: infusion. Left side of figure, pump off, LV pressure 125/10-18 mmHg; 
right side of figure, pump on, synchronous v ith Ecg, LV pressure 90/2-8 mmHg. Note increase of 
aortic pressure from 125/100 (left) to 140/95 mmHg (right). 
to 64 days) ; and awake, at rest in stall or during 
treadmill exercise. 
Two controls, 8 calves with LV blood pumps 
and 4 animals with LV and RV pumps have 
been studied in this form of LV failure, with an 
additional 2 animals having induced RV failure. 
The latter 2 experiments can be dismissed sum- 
marily : right coronary microsphere infusion is 
lethal. The calf with the LV pump alone showed 
good evidence of RV failure, but developed ven- 
tricular tachycardia, episodes of bradycardia, 
and died on the third day after the microsphere 
infusion. The calf with the RV and LV pumps 
had microspheres infused in the left coronary 
artery, as usual, and one third the dose infused 
in the right coronary. Upon arrival at the ani- 
mal farm one hour later, he was found in ven- 
tricular fibrillation. Nine hours later, his aortic 
pressure was steady at 125/85 mmHg. The 
bladder of the right pump bladder then gave 
evidence of rupture, and although this was not 
fatal, the animal was sacrificed. 
The pathological results of the diffuse micro- 
sphere-induced ischemia in the distribution of 
the left coronary artery are illustrated in 
Figure 7. Small islands of normal and hyper- 
trophied myocardium (upper left) are sur- 
rounded by widespread deterioration of myo- 
fibrillar structure, round cell infiltrate and 
proliferating fibroblasts and fibrocytes. Many 
microspheres are visible in this low-power 
photomicrograph of LV myocardium obtained 
21 days after induction (LVedp = 30 mmHg) 
of failure. At sacrifice, the heart weighed 140% 
of comparable controls, and the LVedp was 22 
mmHg. 
The effect of microsphere induced failure on 
ventricular function is illustrated in Figure 8, 
where end-diastolic and end-systolic frames 
from biplane angiograms compare a control 
(above) to a failure (below) calf. The end- 
diastolic volumes were increased in a manner 
comparable to that illustrated in Figure 6, 
and the ejection fraction similarly reduced by 
microsphere infarction (normal calf 48% ; fail- 
ure calf 23% ; Figure 8). 
The hemodynamic effects of this type of 
failure are partially illustrated in Figures 9 
and 10, two different expressions of myocardial 
failure: shock and pulmonary venous hyper- 
tension. Although this particular calf did not 
manifest clinical pulmonary edema, 4 have done 
so, including the calf illustrated in Figure 10. 
This latter recording is from the second study 
of a calf with an LV pump, only, obtained on 
the 46th day of continuous bypass. Total LV 
