Canadian Journal of Anesthesia, Vol 6, 119-129, Copyright © 1959 by Canadian Anesthesiologists' Society

The Effect of Anticholinergic Drugs on the Cardiac Vagus: II, The Cardiovascular Response of Animals to Electroconvulsive Therapy

¹ Departments of Anaesthesia and Pathology, University of Saskatchewan, College of Medicine, Saskatoon, Sask

The acute effects of electroconvulsive therapy have been reinvestigated on animals. Our experiments have shown that the effects of ECT on circulatory dynamics were due mainly to stimuli which reached the heart through the vagus nerves. If these nerves were not blocked, electroshock with a current of duration employed clinically caused a brief period of asystole in almost every experiment, and occasionally caused death, either because of prolonged asystole, or by asystole followed by ventricular fibrillation. The previous administration of an anticholinergic drug in sufficient dosage to block the vagus nerves effectively eliminated the major cardiac reaction to electroshock. The intravenous injection of a moderate dose of thiopental did not appear to alter grossly the cardiovascular response, but did seem to reduce the physical reaction to the electric shock. A small dose of succinylcholine intravenously reduced the reaction of skeletal muscle to the electric shock but did not appear to affect the cardiovascular response to ECT.

Note:

Presented at the Annual Meeting of the Canadian Anaesthetists' Society at Montebello, Que., June 23, 1958.

Dr. Dobkin is an Associate Professor of Anaesthesia. Dr. Olszewski is an Associate Professor of Pathology (Neuropathology) and an established investigator of the National Research Council of Canada.