The role of nerves in the production of cardiac arrest during surgical anaesthesia.

The role of cardiac nerves in the production of cardiac arrest during surgical anaesthesia on coronary ligated hypoxic heart has been studied. When atropinished coronary ligated dogs were exposed to hypoxia the terminal event was a cardiac asystole in 88% of the dogs. In propranolol treated dogs, or in dogs where sympathetic ganglia upto T6 were bilaterally removed earlier, coronary ligation and hypoxia produced ventricular extrasystoles, ventricular tachycardia and repeated sinus arrest followed by ventricular fibrillation. The possibility of the origin of arrythmia from the damaged myocardium, and the presence of an intact vagus in the production of ventricular fibrillation has been discussed.