European Journal of Cardio-Thoracic Surgery, Vol 6, 201-208, Copyright © 1992 by European Association for Cardio-thoracic Surgery
Cardiac denervation in the calf using cryoablation: functional evidence and regional tissue catecholamine content
JA Gaer, J Wharton, L Gordon, RI Swift, C Munsch, GC Inglis, JM Polak and KM Taylor
Department of Cardiothoracic Surgery, Hammersmith Hospital, London, UK.
Twenty-six calves were subjected to a technique of cryoablation in order to
establish an animal model of complete cardiac denervation. All 26 survived
the procedure, and 20 were alive to be re-evaluated 2-4 weeks later. Mean
heart rate in the denervated animals rose from 77 +/- 7.8 beats/min to 102
+/- 16.4 (P less than 0.01). Cryoablation abolished the heart rate
responses to electrical stimulation of the vagus nerve and thoracic
sympathetic trunk. The reduction in myocardial noradrenaline concentrations
averaged 99% in the right atrium, 90% in the left atrium, 85% in the right
ventricle and 90% in the left ventricle, when compared with tissue obtained
from control animals. Cryoablation is a relatively simple means of
accomplishing complete functional cardiac denervation in the calf. On the
basis of the observed change in heart rate, the calf model appears to be
more comparable with human heart transplant recipients than the dog.