180 
CARDIAC MODELS 
Figure 1. — Interrelationship amongst the blood coagulation, fibrinolysin and vasoactive polypeptide 
systems. The role of acid pH in activation of the systems. 
tion. A left side thoracotomy and pericardotomy 
was performed. A single ligature was placed 
loosely around the origin of the anterior de- 
scending branch of the left coronary artery. The 
ends of the ligature were exteriorized through 
the chest wall and the pericardial sac and chest 
wall closed (Fig. 3). After a 7-day recovery 
period, the animals were prepared for record- 
ing of ECG and arterial blood pressure via a 
cannula inserted into the femoral artery (under 
local anesthesia). Control venous blood samples 
were drawn and base line physiologic param- 
eters were obtained. Seven dogs received 
saline, 10 mls/kg, while the other 7 received a 
proteinase inhibitor, TRASYLOL, 50,000 units/ 
kg intravenously just prior to occlusion. The 
coronary ligatures then were tightened sud- 
denly and blood samples drawn at rapid inter- 
vals thereafter. The acute phase was followed 
for 30 minutes and then from 24 hours to 8 days. 
Autopsies were carried out on all animals as 
well as histopathology, but will not be reported 
in this preliminary communication. 
Biochemical-Hematological Studies 
Biochemical and hematologic studies were 
carried out in accordance with previously pub- 
lished methods.^ The following parameters were 
measured : hematocrit, Lee White clotting time, 
prothrombin time, plasma fibrinogen, euglobu- 
lin clot lysis time, kininogen, kinin, kininase, 
and SGOT. 
RESULTS 
Two of the control dogs died acutely after the 
occlusion and one died 24 hours later of heart 
rupture. One TRASYLOL-treated dog died 
acutely while one died after 24 hours. All dogs 
