Abstract
Cover photo. Early Australian defibrillator. Image courtesy of the Geoffrey Kaye Museum of Anaesthetic History, VGKM4612.
When Queen Victoria died in 1901, newspapers reflected on the glorious accomplishments of her reign: ‘Steam and electricity have emerged from the realm of dreams, passed all the stages of experiment, and become the regulated and completely disciplined servants of mankind.’ 1 In reality, though, as the world ticked over into the 20th century, industrial electricity was still in its infancy and the medical world was only on the cusp of understanding its potential risks and benefits.
Electricity first became commercially available in the 1870s when practical generators were developed. 2 The increasing use of electricity, both direct current (DC) and alternating current (AC), resulted in many accidental deaths, particularly among power company employees, but the mechanism of death remained elusive. There were many theories—from a loss of magnetic properties in arterial blood to suffocation and heart failure – but insufficient evidence to support any of them. It was hoped that the first legal electrocution, the death of William Kemmler in an electric chair on 6 August 1890, would provide some answers, but despite the presence of 12 physicians at the execution and an extensive autopsy, the situation remained largely unexplained.
The question was finally answered in 1899, when independent research by Italian physiologists Jean Louis Prevost and Frederic Battelli, and RH Cunningham of Columbia University, demonstrated that strong electric shocks stopped the hearts of experimental animals.3,4 Additionally, they observed that weak shocks caused ventricular fibrillation, which was also fatal. Prevost and Battelli discovered that some of the animals with ventricular fibrillation were restored to sinus rhythm by applying further current through electrodes in the mouth and small intestine. As they were unable to explain this phenomenon, or consistently replicate it, this first successful internal defibrillation went relatively unnoticed. At the time, ventricular fibrillation was thought to occur only in animals but John McWilliam, also writing in 1899, suggested that it may also be a cause of death in humans: ‘It is hardly to be expected that such a widespread and probably universal feature of mammalian cardiac action should be unrepresented in the case of man.’ 5
Augustus Desiré Waller published the first account of a recorded electrocardiograph in 1887, 6 paving the way for Willem Einthoven to develop it into a practical clinical tool. 7 By the 1920s, many arrhythmias had been described and, as the physiology of the heart became clearer, various researchers noted that there appeared to be a refractory period in the cardiac cycle where the ventricles were more susceptible to ventricular fibrillation from an electric shock. In 1940, Carl Wiggers and René Wégria demonstrated this conclusively, establishing that a brief electric shock ‘induces fibrillation only when the shocks fall during the vulnerable period of late systole.’ 8
During this time, as electrocardiography was developing, research into resuscitation continued. Louise Robinovitch (sometimes Rabinovitch), a pioneer in the use of medical electricity, noted: ‘It is possible to resuscitate, by means of electric current, subjects in a condition of apparent death caused by chloroform, ether, morphin [sic], electrocution, etc.’ 9 Robinovich had been championing the cause of electricity as an anaesthetic, as well as a means of resuscitation. By 1911, she had developed several pieces of apparatus, including a portable resuscitation device for use in ambulances. Her preferred equipment produced ‘a direct current, interrupted from 6,000 to 8,000 times per minute, period 1/10’, generating ‘artificial blood pressure and respirations by means of rhythmic electric excitations’. 9 She noted the limitations to human resuscitation, including the reality that resuscitation beyond four to five minutes of cardiac arrest was unlikely to have a positive outcome. With this in mind, she recommended that her machine should be attached prophylactically prior to chloroform anaesthesia, with one electrode under the chest and another under the loin, to be activated at the first sign of trouble: ‘The surgeon does not fold his arms and wait until both the respiration and the heart have failed’. 9 Due to a lack of understanding of the basic physiology and the intervention of World War I, little resulted from Robinovitch’s work.
By the 1920s, alternating current had become the standard power and the few remaining DC generators were shut down. Funding provided by power companies led to collaborative projects, such as that between the medical faculty and engineer William Kouwenhoven at Johns Hopkins University. Kouwenhoven and colleagues conducted years of research into the effects of electricity on the heart, publishing several articles in the Journal of Physiology in the early 1930s. In 1933, acknowledging the earlier work of Prevost and Battelli, they definitively established that electrically induced ventricular fibrillation could be reversed with an appropriate counter-shock. 10
Claude Beck, Professor of Surgery at Case Western University, Cleveland, having closely followed the work of Kouwenhoven and of Wiggers, developed an alternating current defibrillator for internal defibrillation. 11 He used this for the first successful human defibrillation in 1947 when a 14-year-old boy suffered a prolonged period of ventricular fibrillation during an operation for pectus excavatum. The chest was already open, the fibrillating heart was fully visible and the paddles applied directly to the heart; after four shocks of 110 V, the boy made a full recovery. Around the world, others were working on similar technology with considerable debate about the potential for external transthoracic defibrillation as a means of resuscitation. Many, like Wiggers, felt the shock required would be damaging to the heart and defibrillators would only have a future in operating theatres where the chest was open.
Harvard cardiologist Paul Zoll, researching external pacing for Stokes Adams attacks, became convinced of the safety of external defibrillation. 12 At his request, Electrodyne constructed a machine with a large transformer to convert 120 V wall outlet power to 720 V. The machine was bulky and heavy but could be moved with difficulty on wheels. In 1956, Zoll reported four patients successfully reversed from ventricular fibrillation to sinus rhythm. Overall, 11 shocks were administered, all of which reversed ventricular fibrillation for a time, but only one of the patients survived to leave hospital. This patient also had an episode of ventricular tachycardia reversed by the defibrillator, ‘suggesting that this procedure may prove valuable clinically in stopping other arrhythmias as well as ventricular fibrillation’. 12
Bernard Lown and colleagues brought all the earlier research together in 1962 when they reported the use of DC current from a synchronised capacitor for the treatment of cardiac arrhythmias. 13 They noted the work of Prevost and Battelli with DC current and Kouwenhoven and Zoll with AC defibrillators, as well as important work by Czech and Russian researchers with DC square wave capacitor discharges. The brief pulse wave generated by these capacitors allowed synchronisation with any given part of the cardiac cycle. Lown’s work allowed for synchronised shocks and the subsequent development of small portable defibrillators, a standard feature of modern resuscitation. It is now recognised that early defibrillation ‘provides the best chance of survival in victims with VF or pulseless VT.’ 14