434 
SURGERY AND TRANSPLANTATION 
gradual enhancement of myocardial contractile 
state in the denervated animals throughout the 
first few minutes of running, due possibly to the 
operation of a humoral mechanism such as cir- 
culating catecholamines. This hypothesis is 
being further examined by analysis of instanta- 
neous velocity-length-tension relationships and 
by observation of the effects of beta-adrenergic 
blockage prior to exercise. 
REFERENCES 
1. Donald, D. E., and Shephered, J. T. Responses 
to exercise in dogs with cardiac denervation. Am. 
J. Physiol. 205:393-400, 1963. 
2. Donald, D. E., and Shephered, J. T. Sustained 
capacity for exercise in dogs after complete cardiac 
denervation. Am. J. Cardiol. 14:853, 1964. 
3. Stinson, E. B., Griepp, R. B., Clark, D. A., 
Dong, E., Jr., and Shumway, N. E. Cardiac trans- 
plantation in man. VIII. Survival and function, J. 
Thorac. and Cardiovasc. Surg. 60:303, 1970. 
4. Stinson, E. B., Griepp, R. B., Schroeder, J. S., 
Dong, E., Jr., and Shumw^ay, N. E. Hemodynamic 
observations one and two years after cardiac trans- 
plantation in man. Circulation. In press. 
5. Cooper, T., Gilbert, J. W., Bloodwell, R. D., 
and Crout, J. R. Chronic extrinsic cardiac dener- 
vation by regional neural ablation. Description of 
the operation, verification of the denervation, and 
its effects on myocardial catecholamines. Circula- 
tion Res. 9:275-281, 1961. 
6. Barger, a. C, Richards, V., Metcalfe, J., and 
Gunter, B.: Regulation of the circulation during 
exercise. Cardiac output (Direct Fick) and meta- 
bolic adjustments in the normal dog. Am. J. Phy- 
siol. 184:613, 1956. 
7. Bailie, M. D., Robinson, S., Rostorfer, H. H., 
and Newton, J. L. Effects of exercise on heart 
output of the dog. J. Appl. Physiol. 16:107, 1961. 
8. Cerretelli, p., Piiper, J., Mangili, F., Cuttica, 
F., and Ricci, B. Circulation in exercising dogs. J. 
Appl. Physiol. 19:29, 1964. 
9. Schuette, W. H., and Simon, A. L. A new device 
for recording cardiac motion. Med. Res. Eng. 7:25, 
1968. 
10. Ashkar, E., and Hamilton, W. F. Cardiovascular 
response to graded exercise in the sympathectom- 
ized vagotomized dog. Am. J. Physiol. 204:291, 
1963. 
DISCUSSION 
Chairman Hamlin : Did you have an oppor- 
tunity to measure diastolic compliance or sys- 
temic arterial pressures in any of these that 
might help account for the increase in end dia- 
stolic volume in the denervated dogs ? 
Dr. Stinson : In this particular group of ani- 
mals we didn't make any attempt to analyze 
diastolic ventricular compliance. In a few ani- 
mals, in the initial portion of the series, arterial 
pressures were measured concomitantly with 
the other parameters. Changes in arterial pres- 
sure with the onset of exercise were similar to 
peak developed left ventricular pressures that I 
illustrated. Interestingly, it showed very mini- 
mal, if any, increase with the onset of running. 
This sort of resembles the response of a normal 
animal who has been given propanolol prior to 
exercise. 
Dr. Hamlin : Why do you suppose end dia- 
stolic volume and pressure increased? 
Dr. Stinson : Well, there are several lines of 
evidence which show that the metabolic vasodi- 
latation associated with the onset of exercise 
does results in an increase in ventricular filling 
or venous return, if you will. In the absence of 
elevation of ventricular afterloads, then I must 
assume that it's an increase in preload which 
accounts for the initial changes in diameter and 
pressure. In addition to the metabolic vasodila- 
tation associated with the onset of muscular 
exercise. Gulden has shown that there is a trans- 
location of blood from peripheral pools to the 
central circulation with the onset of muscular 
exertion. It's my assumption that this accounts 
for the increased ventricular filling. 
D, C. Sawyer, Michigan State, East Lansing : 
Since you set out to do this study as a compari- 
son to those human transplanted patients, why 
did you select the dog and did you consider 
species other than the dog ? 
Dr. Stinson: Well, we considered man of 
course but it's a little more difficult to measure 
these parameters in man. I've not had the expe- 
rience to seriously entertain other species of an- 
imals for treadmill exercise. Do you have any 
suggestions ? 
Dr. Sawyer : The pig runs great on a tread- 
mill. 
Chairman: Did you try to simulate Donald's 
and Shepherd's studies by exercising dogs with 
denervation plus propanolol ? 
Dr. Stinson: Yes we did. Although these 
studies are in the initial stages of analysis at 
