Electrical Induction of Ventricular Fibrillation in the Human Heart

Abstract

An experimental study was made on induction thresholds for ventricular fibrillation with alternating currents at frequencies ranging between 6 and 1 600 c/s. The tests were performed on experimental dogs and on patients in association with open-heart surgery. The most vulnerable range was found to be between 12 and 60 c/s. A close similarity was demonstrated between canine and human hearts. The induction of ventricular fibrillation during open-heart surgery is discussed. Ventricular fibrillation, caused by electricity, is either accidental or deliberately induced for medical purposes. The myocardial threshold of excitability towards alternating currents is dependent on two parameters, current and frequency. The vulnerability of the heart towards current has been thoroughly investigated by several authors (Walter, 1969; Dalziel & Lee, 1969; Nickel & Spang, 1965; Kugelberg, 1975). A frequency of 50–60 c/s was utilized in all these determinations, as this is the one of choice in networks for distribution of electric power all over the world. Thus, accidental ventricular fibrillation is most likely to occur with currents of this frequency, and inductions for medical purposes, i.e. during open-heart operations, are achieved in the easiest way with simple transformers delivering the same frequency.

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Notes on contributors

Jan Kugelberg

Joyce Laing works in the Department of Child and Family Psychiatry, Playfield House, Cupar, Fife, and is a Consultant Art Therapist to Psychiatric Hospitals and Prisons and Chairwoman of the Scottish Society of Art and Psychology.