J. ROSENWEIG AND S. CHATTERJEE 
121 
(A) (B) 
Figure 2. — Angiograms of counterpulsated dogs show- 
ing (a) no intercoronary collateral circulation: how- 
ever, marked homocoronary circulation from promi- 
nent septal and anterior left ventricular diagonal 
arteries (b). 
Experiment III— Metabolic Study 
Nine adult mongrel dogs were operated upon. 
Coronary artery constrictors were placed as in 
Experiment I. Blood samples were drawn from 
the aorta and coronary sinus for lactate and 
pyruvate concentration. On the 14th day, by 
right thoracotomy, a cannula penetrating the 
right atrial wall was inserted into the coronary 
sinus and its distal end brought out through 
the chest wall (Figure IC). Following closure 
of the incision, the animal was counterpulsated. 
Aortic and coronary sinus blood samples were 
drawn immediately prior to and following coun- 
terpulsation for lactate and pyruvate concentra- 
tion. The coronary sinus lactate concentration 
was then repeated daily for three days. 
RESULTS 
Experiment I 
Seven of the nine control animals died within 
thirty days. The other two died on the thirty- 
second and forty-fifth day, respectively. Mean 
survival in control animals was 23.5 days. How- 
ever, all treated dogs survived the one month 
period. Two animals died on the thirty-first 
day and thirty-seventh day and eight animals 
lived beyond ninety days and were later sacri- 
ficed. Mean survival to time of death or sacri- 
fice in the treated group was 91.3 days. The 
difference in mean survival between the un- 
treated and counterpulsated animals was strik- 
ingly significant (t = 6.5, P < 0.001). 
Mean coronary artery constriction at time of 
death in control animals was 66 percent and 65 
percent in the anterior descending and circum- 
flex artery, respectively; whereas treated dogs 
revealed 93 percent and 93 percent, respectively. 
Postmortem angiograms were assessed in terms 
of collateral circulation to the distal branches 
of proximally occluded anterior descending and 
circumflex arteries. Three primary sources for 
collateral circulation were apparent — the right 
coronary artery, the septal artery, and diagonal 
anterior left ventricular branches arising di- 
rectly from the left main coronary artery prox- 
imal to the constrictors. 
In the control group, eight of the nine dogs 
revealed no intercoronary collateral circulation, 
whereas only two of the ten counterpulsated 
animals showed no right to left intercoronary 
anastomotic vessels. In six treated dogs, there 
was excellent intercoronary circulation. Homo- 
coronary collateral circulation was also more 
obvious in the counterpulsated group. The sep- 
tal artery was prominent in every treated dog 
with numerous arborizing vessels communicat- 
ing with branches of the anterior descending 
and circumflex arteries. In addition, diagonal 
anterior left ventricular arteries arising prox- 
imal to the constrictors (not seen in control 
animals) also communicated with branches of 
the anterior descending and circumflex arteries 
(Figures 2 and 3). 
Histologic examination revealed increased 
prominence and number of subepicardial as well 
as intramyocardial arteries and arterioles in 
treated dogs. Myocardial infarction was not de- 
tected in the hearts of counterpulsated animals, 
but was observed in five of the nine control 
animals. 
