E. L. STANLEY, P. KEZDI AND R. K. KORDENAT 
159 
tometer) were recorded and blood samples 
drawn for SGOT determination. Cardiac output 
was measured in duplicate and the average of 
the two measurements was used. All animals 
were evaluated up until the time of death or 
sacrificed by the fourteenth day. 
Postmortem examinations were performed in 
all animals with measurement of the size and 
the weight of the myocardial infarction. The 
helical coil obstructed site was dissected out and 
histologic sections of the thrombosis obtained. 
The time of infarction was determined by the 
ECG changes, elevation of the SGOT, and the 
appearance of the myocardium at the time of 
postmortem examination. 
The animals studied were divided into three 
groups. In the first group the consequences of 
the gradual occlusive process at the helical coil 
site were evaluated without intervention other 
than the treatment of serious arrythmias. Coro- 
nary occlusion with myocardial infarction oc- 
curred 16-24 hours after helical coil insertion 
in this group of animals. The second group of 
animals was pretreated with heparin, 4,000 
units intravenous in one dose, to evaluate pro- 
longation of occlusion time. This anticoagula- 
tion technique with heparin prolonged the aver- 
age time of occlusion and myocardial infarction 
to approximately 48 hours. In the third group 
of animals a shortening of the occlusive time 
was evaluated by injection of a 0.1% solution of 
palmitic acid into the coronary artery branch at 
the site of the helical wire. Immediate occlusion 
by clotting at the site of the helical wire oc- 
curred in one to two minutes. 
RESULTS 
Clinical Course, Electrocardiographic, and 
Hemodynamic Changes 
In 43 dogs the helical coil wire was placed in 
either the left anterior descending (24) or the 
left circumflex artery branch (19). In the left 
anterior descending branch the wire was distal 
to the septal but proximal to the first major epi- 
cardial branch. Occlusion at the wire site with 
distal infarction occurred within the first 24 
hours in 21 of the 24 animals. One animal died 
due to arrhythmia one hour after wire place- 
Table I. — Myocardial Infarction by Helical Wire Place- 
ment in U5 Dogs 
Left 
Circumflex 
Anterior 
Descending 
Total 
% of 46 
Attempts 
Successful 
19 
24 
43 
94 
Survival > 48 
hours 
9 
18 
27 
63 
Infarction 
12 
21 
33 
77 
Acute arrhythmia 
1 hr. 
2 
1 
3 
7 
Failure to clot 
5 
2 
7 
16 
Average survival 
8 days 
11 days 
Average infarct 
wt. 
22 gm. 
20 gm. 
Average heart wt. 
154 gm. 
152 gm. 
Results of selective placement of helical wires in the left coronary 
artery using the double catheter technique. 
ment, and on two occasions the wire was prop- 
erly positioned, but no clot occurred. Those ani- 
mals who survived longer than 24 hours lived 
an average of 11 days with an average infarc- 
tion weight of 20 gms (Table I) . 
In the 19 animals with wire placement in the 
left circumflex artery the helical wire was in 
the proximal 2 cm in 17 of the 19 animals. In 
two animals the wire descended to the marginal 
branch and both animals died within one-half 
hour due to arrhythmia. In five animals the hel- 
ical wire failed to clot due to the small (less 
than three coil) size. The average survival time 
of the animals with left circumflex artery occlu- 
sion was eight days with an average infarction 
weight of 22 gms. Serial ECG's of all animals 
following wire placement showed a similar pat- 
tern of evolution the first 24 hours (Figure 2). 
There was an initial tachycardia which in a pe- 
riod of six to eight hours increased up to rates 
of 160 with AV dissociation and idioventricular 
tachycardia. This AV dissociation and idioven- 
tricular tachycardia was not significantly af- 
fected by antiarrhythmic agents such as prones- 
tyl or lidocaine whereas the appearance of 
premature ventricular beats was controlled by 
these drugs. The initial ST depression pro- 
gressed to ST elevation and Q waves developed in 
the appropriate leads of the ECG. The AV dis- 
sociation and idioventricular tachycardia per- 
sisted for 24-48 hours and in those animals that 
survived longer than three days reverted back 
to a normal sinus rhythm. The ST-T wave dem- 
onstrated a normal evolutionary pattern with 
return to the base line within four to ten days. 
Serial hemodynamic values were compared in 
