The electrophysiology of electrocution

Abstract

Electrocution is a death caused by an application of electrical current to the human body. Our present understanding of electrocution-as the induction of ventricular fibrillation (VF)-followed a nearly century-long path of misunderstandings and speculation primarily focused on hypotheses of asphyxia as well as central nervous system trauma. It is hard for us today to appreciate the past mystery of an unexpected sudden death usually bereft of visible trauma. Even today, a false dogma exists that direct-current shocks can cause asystole instead of VF. A lightning discharge (up to 500 megavolts) is differentiated because it can cause substantial acute and chronic neural effects leading to other cardiac arrest rhythms. The human heart is exquisitely sensitive to alternating currents, and VF can be induced with currents of one-eighth that required for mere pacing. Because of these low currents, this effect obtains only in the TQ interval, and low-power electrocution does not involve the vulnerable period. If a current is strong enough to electrocute, generally it will do so in 1-2 seconds; longer shocks do not tend to be more dangerous. Regardless of concomitant drug dosing, the electrocution cardiac arrest rhythm is still VF, suggesting that electrocution is a stand-alone cause of death; the electrical current does not potentiate the effects of the drug. The experimental and clinical data supporting VF as the mechanism for electrocution are provided.

Keywords: Alternating current; Asphyxia; Asystole; Cardiac arrest; Direct current; Electrocution; Ventricular fibrillation.

Figure 1

Examples of alternating current (AC) (60 Hz), direct current (DC), and pulse current.

Figure 2

Hoffa and Ludwig’s demonstration of electrically induced fibrillation. (From Hoffa and Ludwig.²)

Figure 3

Canine arterial pressure (vertical axis) after fibrillation by 20-V alternating current (AC) and defibrillation by 4800-V AC. (From Prevost and Batelli.⁸)

Figure 4

A: Electrogram showing 60-Hz interference followed by ventricular fibrillation (VF) detection after electrical source is released. B: VF is terminated by implantable cardioverter-defibrillator shock. (From Ginwalla et al and used under STM permission guidelines.)