102 CARDIAC 
effect of the diet and drug regimen, but the 
mechanism by which this enhancement is ac- 
complished is unknown. 
We have used the phrase "sudden death" to 
refer to any death in which preceding signs of 
severe illness were not recognized in the swine. 
Since most of those that died suddenly had one 
or more myocardial infarcts, it is obvious that 
they did actually have severe preceding disease. 
On 16 swine that died suddenly terminal elec- 
trocardiograms were obtained; 10 showed ven- 
tricular fibrillation and 6 showed ventricular 
asystole. In man with coronary heart disease 
dying suddenly, it is usually speculated that 
they died of ventricular fibrillation. Cobb et al.^ 
reported recently that ventricular fibrillation 
was the main cardiac arrhythmia among pre- 
hospital emergency cardiac cases treated by 
their mobile intensive/coronary care unit. Since 
the immediate cause of death in those 16 swine 
dying suddenly was proved to be either ventric- 
ular fibrillation or ventricular asystole, it is 
reasonable to assume that many or most of the 
swine that died suddenly in our previous experi- 
ments had cardiac arrhythmias. 
SUMMARY 
The swine model developed in the current 
study should be of considerable value in studies 
of sudden death and also for the scientific trial 
of therapeutic devices and surgical procedures 
prior to their use in man. 
REFERENCES 
1. Thomas, W. A., Plorentin, R. A., Nam, S. C, 
Kim, D. N., Jones, R. M., and Lee, K. T. Pre-pro- 
liferative phase of atherosclerosis in swine fed cho- 
lesterol. Arch. Path. 86:621-643, 1968. 
2. Florentin, R. a., and Nam, S. C. Dietary-induced 
atherosclerosis in miniature swine. I. Time of devel- 
opment and morphologic characteristics of lesions. 
Exp. Mol. Pathol. 8:263-301, 1968. 
3. Lee, K. T., Jarmolych, J., Kim, D. N., Grant, C, 
Krasney, J. A., Thomas, W. A., and Bruno, A. M. 
Production of advanced coronary atherosclerosis, 
myocardial infarction and "sudden death" in swine. 
Exp. Mol. Pathol. 15:170-190, 1971. 
4. Daoud, a. S., Jarmolych, J., Zumbo, 0., Fani, K., 
and Florentin, R. Pre-atheroma phase of coronary 
atherosclerosis in man. Exp. Mol. Pathol. 3:475-484, 
1964. 
MODELS 
5. Fajardo, L. F., and Steward, J. R. Experimental 
radiation-induced heart disease. Amer. J. Pathol. 
59:299-315, 1970. 
6. Cobb, L. A., Conn, R. D., and Samson, W. E. Pre- 
hospital coronary care: The role of a rapid response 
mobile intensive/coronary care system. Circulation 
44 (Suppl. II) :45, 1971. 
DISCUSSION 
Chairman Kezdi : Dr. Lee, your coronary an- 
giograms look frighteningly similar to human 
coronary angiograms. I just would like to ask 
you one question. When you irradiated the ani- 
mals, you irradiated the chest. Do you believe 
that the same thing would occur if you irra- 
diated the abdominal area? 
Dr. Lee: Yes, we like to think so. In other 
studies, we are now irradiating the carotid ar- 
teries. We have preliminary data indicating 
that this produces quite an advanced lesion. 
However, we have not done the abdominal 
aorta; but I have every reason to believe that 
the result should be the same. 
Thomas C. Militano, NIH, Bethesda, 
Md. : In our previous liscussions, Dr. Lee, you 
indicated to me that you felt that the role of the 
X-ray was merely to produce intimal damage, so 
that it accelerated the effect of the cholesterol, 
and you indicated that there were other tech- 
niques that you were considering to produce int- 
imal damage. One of those you mentioned inter- 
ested me because it was a generalized technique, 
a serum sickness type model. I wonder if you 
could comment on that? 
Dr. Lee: Yes, we talked previously about 
X-ray injury. We like to think that X-ray causes 
ionizing damage to the endothelial cells or cellu- 
lar wall and the latter increases the rate of 
filtration of lipids into the intimal cells and this 
in turn accelerates the development of the lesion. 
In regard to other methods of producing ather- 
osclerotic lesions, we have previously demon- 
strated that an injury more comparable to a 
naturally-occurring injury, experimental serum 
sickness, in combination with a hypercholestero- 
lemic diet, resulted in enhancement of ather- 
osclerotic lesions in aortas of rabbits. However, 
we have not yet tried this technique in swine. 
H. L. Brooks, University of Chicago: Dr. 
Lee, do you believe that you could find some way 
