296 
SURGERY AND TRANSPLANTATION 
I 
tion to myocardium and nodal tissue, and (2) 
to provide models for preparation of animals 
with well-defined partial cardiac denervation. 
METHODS 
Seventeen mongrel dogs were pre-medicated 
with phencyclidene hydrochloride (2 mg/kg 
I.M.) and anesthetized with a-chloralose (80 
mg/kg I.V.). Positive pressure respiration was 
instituted, the chest was opened bilaterally, and 
a pericardial cradle constructed. Walton-Brodie 
strain gauge arches were sutured to the right 
atrium (RA), left atrium (LA) and right ven- 
tricle (RV). Systemic pressure was monitored 
from a cannula in the femoral artery. All data 
were recorded on a Model 1 Grass Polygraph. 
Both vagosympathetic trunks were tran- 
sected in the neck, the anterior and posterior 
ansae were divided bilaterally at their origin 
from the stellate ganglia and the mediastinal 
cardiac nerves were isolated within the media- 
stinum for subsequent stimulation. The nerves 
were designated by the terminology of Mizeres:^ 
anterior and posterior ansae, recurrent cardiac, 
craniovagal, caudovagal, stellate cardiac, ventro- 
lateral cardiac (VLCN), ventro-medial cardiac 
(VMCN), innominate, cervical vagosympathetic 
trunks and the thoracic vagus nerves. 
A series of ablation procedures was per- 
formed to selectively interrupt extrinsic cardiac 
nerve pathways as they enter the heart. Each 
of the autonomic nerves with cardiac efferent 
distribution were electrically stimulated supra- 
maximally with square wave impulses of 10 Hz, 
5 msec duration and 6 volts prior to intervention. 
Each of the nerves was subsequently stimulated 
following each of the ablation procedures. 
Figure 1 depicts the interventions: (1) tran- 
section and re-anastomosis of the intra-peri- 
cardial superior vena cava (SVC) from its 
junction with the superior margin of the left 
atrium to the anterior SVC ; (2) transection and 
re-anastomosis of the lateral portion of the 
intra-pericardial SVC from the anterior SVC 
to the level of the right superior pulmonary 
vein; (3) excision of neural elements, epicar- 
dium and areolar tissue in the inter-atrial 
groove from the right superior pulmonary vein 
to the right inferior pulmonary vein (inter- 
atrial groove [TAG] ) ; (3) transection and re- 
anastomosis of the anterior border of the LA 
from the margin of the inferior vena cava 
(IVC) with the LA to the left inferior pulmon- 
ary vein; (5) transection and re-anastomosis 
of the lateral border of the LA from the left 
inferior pulmonary vein to the left superior 
pulmonary vein; (6) transection and re-anasto- 
mosis of the superior border of the LA in the 
transverse sinus from the left superior pul- 
monary vein to the medial SVC; (7) circum- 
ferential transection of adventita and neural 
elements on the left half of the ascending pul- 
monary artery; (8) circumferential transection 
of adventitia and neural elements on the right 
half of the pulmonary artery and on the left 
half of the ascending aorta; (9) transection of 
the VLCN as it enters the heart at the origin 
of the left superior pulmonary vein; (10) cir- 
cumferential transection of adventitia and neu- 
ral elements on the right half of the ascending 
aorta. In six experiments the procedures were 
performed in the order described above; in 
six further experiments the procedures were 
performed in the reverse order ; in the remain- 
ing five experiments the areolar tissue and neu- 
ral elements located at the junction of the IVC 
Figure 1. — Regional Denervation of the Canine Heart. 
Method of Regional Cardiac Denervation 
