J. ROSEN WEIG AND S. CHATTER JEE 
123 
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^ *>, 13 X> }« 3i 3« ^* 3? to 
['.^ Nn 1 B 10 II 13 w s 0 
Figure 5. — Composite histograms of coronary flow in 
control dogs and animals treated by counterpulsation. 
both groups, namely 74 percent and 73 percent, 
respectively in the anterior descending and cir- 
cumflex artery in untreated controls and 76 
percent and 76 percent, respectively, in the 
counterpulsated dogs. 
Angiograms revealed retrograde filling of 
the occluded arteries from the same three 
sources observed in Experiment I. Retrograde 
filling of the anterior descending and circum- 
flex artery systems was achieved through anas- 
tomotic branches of the right coronary artery 
and the septal artery. In counterpulsated dogs, 
both vessels were larger and showed more ex- 
tensive arborization. Other sources of collateral 
flow were diagonal anterior left ventricular 
branches (arising proximal to the constrictors) 
that were not initially apparent when con- 
strictors were placed. Four of the six treated 
dogs had good to excellent intercoronary col- 
lateral circulation but only one dog in the con- 
trol group revealed intercoronary collateral flow 
(Figure 11). Similarly, homocoronary collateral 
circulation was profuse in all counterpulsated 
dogs, but in only two untreated animals (Figure 
12). 
Mycardial infarction was detected histologi- 
cally in four of the seven untreated animals but 
was not observed in counterpulsated dogs. These 
observations correlated with increased number 
and prominence of subepicardial arteries, as 
well as of branching intramyocardial arteries 
and arterioles coursing through the septum 
and left ventricular myocardium in counterpul- 
sated dogs (Figures 6 and 7). 
Experiment III 
Lactate concentration in the arterial and cor- 
onary sinus blood increased progressively fol- 
lowing application of constrictors (Figure 8). 
Initially the lactate concentration was greater 
in the arterial blood (mean arterial concentra- 
tion was 2.6 mM./L., coronary sinus 2.3 
mM./L.). Comparison of initial and pre-coun- 
terpulsation values indicates that the increased 
levels of lactate concentration were significant 
(arterial t = 2.88, P < 0.05; coronary sinus 
t = 4.6, P < 0.01). 
Following counterpulsation mean lactate con- 
centration was reduced in both the samples 
(arterial 2.6 mM./L., coronary sinus 2.3 
mM./L.), but the coronary sinus concentration 
was less than the arterial concentration. Cor- 
onary sinus lactate concentration three days 
post-counterpulsation remained low (2.3 mM./ 
L.), not significantly different from the initial 
level. 
Excess lactate was calculated according to 
Huckabee's formula.^ Mean excess lactate ini- 
tially was negative (—0.3 mM./L.), but on the 
fourteenth day prior to counterpulsation, it be- 
came positive (0.2 mM./L.), denoting anaerobic 
myocardial metabolism (Figure 16). Following 
counterpulsating, however, mean excess lactate 
became negative again (—0.1 mM./L.) indicat- 
ing that the myocardium was no longer produc- 
