300 
SURGERY AND TRANSPLANTATION 
tation of contractility in the RA was invariably 
accomplished. 
Left Atrium 
Interruption of the inotropic response in 
the LA to stimulation of the right stellate 
cardiac nerve and the recurrent cardiac nerve 
was accomplished by transection of the SVC 
on all occasions. The response to VMCN 
stimulation was interrupted by transection of 
the superior LA in all experiments. The VLCN 
response in the LA was partially interrupted by 
transection of the superior LA, but usually 
required transection of the VLCN at the left 
superior pulmonary vein for total ablation of 
inotropic response in the LA. The inotropic re- 
sponse in the LA to stimulation of the right and 
left ansae was interrupted by a combination 
of transection of the superior LA and by inter- 
ruption of nerves along the root of the great 
vessels. On one occasion, the response to stimula- 
tion of the right posterior ansa and left an- 
terior ansa was not completely interrupted 
until transection of the inferior LA was ac- 
complished. 
In Figure 4 electrical stimulation of the left 
posterior ansa results in augmentation of con- 
tractile force in the RA, the LA (RAF and 
LAF) and in the RV (RVF) associated with 
cardio-acceleration. Following transection of 
the superior margin of the LA (column-superior 
LA), the augmentation of contractile force in 
the RA and LA no longer occurs, while aug- 
mentation in the RV as well as the cardio- 
acceleration continues. The sympathetic fibers 
from this nerve reach both the RA and LA by 
BP 
mmHg 
200 
100 
CONTROL 
LT. POST. ANSA 
SUPERIOR LA 
RIGHT PA 
— r- 
RAF 
BE(RA) 
LAF 
RVF 
BE(RV) 
ECG — 
HRi7i 
214 171 
214 154 
154 
Figure 4. — Regional Denervation of the Canine Heart. 
Lt. Posterior Ansa Stimulation 
BP = blood pressure 
RAF = rt. atrial contractile force 
BE(RA) = bipolar electrogram, rt. atrium 
LAF=lt. atrial contractile force 
RVF=rt. ventricular contractile force 
BE (RV) = bipolar electrogram, rt. ventricle 
