84 
CARDIAC MODELS 
LV-Ao BLOOD PUMP-CHRONIC 
CONTROL LV FAILURE 
Coif )t>l57 
Figure 5. — Pressure recordings before (upper left) and during (upper right and 
lower panel) acute, reversible LV failure induced by inflation of a coronary 
balloon cuff occluder. The control state (upper left) is followed by induced 
failure (upper center), hemodynamically corrected by the LV blood pump 
(upper right, lower left). A biplane anigogram was recorded between upper 
and lower panels. Non-assisted pressures (lower right) following biplane con- 
firms stability and profundity of failure state. Ao,LV = aortic and left ven- 
tricular pressures: LVed = LV end-diastolic pressure, 5x amplified; pump 
SV = electrical pump stroke signal (baseline = full). 
lustrated in a standard chest x-ray obtained 
in one of these animals (32 hours), Figure 11. 
Figure 12 illustrates the transition from nor- 
mal sinus rhythm to ventricular fibrillation in 
the calf whose circulation was successfully 
maintained for 17 days at a cardiac output of 
6.6 to 7.3 liters per minute. Pressures, likewise, 
remained normal, as illustrated and tabulated 
in Figure 12, and as measured daily throughout 
the 17 days. Biplane angiograms, performed 
after 24 hours of ventricular fibrillation con- 
firmed the adequacy of pump maintenance of 
the circulation. 
DISCUSSION 
The principal object of this series of studies 
was the development of reliable techniques for 
the creation of stable, reproducible, acute- 
reversible and chronic-irreversible animal mod- 
els of left ventricular myocardial failure. What 
concluded the search was the development of so 
excellent a model of acute, chronic, and com- 
pensating failure that no more useful model 
could be envisioned for the study of ventricular 
bypass pumps. All that remains is the develop- 
ment of a model of severe, chronic, but reversi- 
ble ischemic failure: the analog of acute myo- 
cardial infarction. 
