J. ROSENWEIG AND S. CHATTERJEE 129 
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1. 
2004 
160- 
so- I 
Qi^ogMAL j cmrreRPumriON 
Figure lu. — b. Electoocardiographic and aortic pressure tracings prior to and during intra-aortic 
balloon counterpulsation in a normal dog. Note slight reduction in systolic pressure, but marked 
augmentation of diastolic pressure. 
desired by simply clamping or releasing the 
pulse pressure generator inflow line. In this ex- 
periment, a disposible Temptrol (Bentley Cor- 
poration, Norwalk, Connecticut, U.S.A.) oxy- 
genator was incorporated into the system for 
synchronous pulsatile venoarterial bypass and 
the pulse generator was hydraulically moti- 
vated by a SIMAS controller (Figure 12). 
RESULTS 
Group I— Untreated Control— Survival 
Survival time, once shock was manifest, aver- 
aged 72.5 minutes (30-135 minutes). Serial 
coronary artery ligation produced increasing 
cyanosis of the anterior surface of the left ven- 
tricle and progressive dilation. Death resulted 
in each instance from ventricular fibrillation. 
Ventricular fibrillation developed when left 
atrial pressure averaged 18 mm. Hg. (range 
15-22 mm. Hg.). Attempts to resuscitate the 
heart by cardiac massage and defibrillation 
were always unsuccessful. The hemodynamic 
and metabolic findings are graphically illus- 
trated (Figure 13). 
Group II — Arterio-Arterial Counterpulsation — 
Survival 
All dogs in cardiogenic shock treated by 
arterio-arterial counterpulsation survived the 
experiment, and eight were subsequently sacri- 
ficed twenty-four hours later. Two dogs died 
twenty-two hours post-operatively from atelec- 
tasis and hemothorax. At autopsy, no dogs 
showed evidence of myocardial infarction. The 
hemodynamic and metabolic findings are in- 
dicated in Figure 14. 
Group III— Intra-Aortic Balloon Counterpulsation 
— Survival 
All animals survived the four hour treatment 
period. Hemodynamic and metabolic param- 
