Defibrillation AC to DC in America and Beyond

Meanwhile, in the United States, defibrillation research had been following a different path altogether, the path of AC and surgical applications. One of the colleagues who paid attention to Wiggers's research at Western Reserve University was Dr. Claude S. Beck, professor of cardiovascular surgery. Beck developed an interest in fibrillation after losing a young patient to ventricular fibrillation in the late 1920s, and closely followed Hooker's and Kouwenhoven's experiments on open-chest defibrillation on animals throughout the 1930s. He performed experiments himself as well and developed a procedure that worked in dogs and monkeys. In 1947 Beck successfully performed the first documented defibrillation on a human patient. Richard Heyard, aged 14, was undergoing surgery to correct a "hollow chest" breastbone malformation. Near the end of the procedure, his heart suddenly entered ventricular fibrillation. The surgeon immediately started direct heart massage, keeping Heyard's blood in circulation, but the fibrillation showed no indication of stopping spontaneously. Beck requested permission to perform his experimental procedure, connecting two electrodes directly to Heyard's exposed heart. After four shocks of 110 V, the fibrillation ceased, and this time mere seconds of heart massage sufficed to restore heartbeat. Richard made a complete recovery, and the case became a deservedly publicized news item, under a variety of titles such as "How Science Brings Americans Back from the Dead."34'35 The case was also published in JAMA by Beck, Pritchard, and Feil.36 Beck continued his research on mechanical means of resuscitation, pioneered the use of a combined defibrillator and heart massage device, and designed the first program to teach laypeople CPR (Fig. 9).

Although Beck was successful with AC defibrillation applied directly to the heart, research on transthoracic defibrillation was beset by more difficulties. After his initial success with open-chested defibrillation of dogs, William Kouwenhoven, dean of the School

First Defibrillator
Figure 9: Beck's first defibrillator, Claude Beck

of Engineering at Johns Hopkins University and bearer of an honorary medical degree from its medical school, directed his research toward developing a portable external defibrillator. After initial attempts with DC designs in the early 1950s, he had to abandon the idea; batteries powerful enough to create the necessary charge simply did not exist at the time. Switching to AC-powered models instead, Kouwenhoven found success in 1951, with a device funded by the Edison Electric Institute. In 1957 he developed a closed-chest defibrillator that used AC to deliver repeated shocks of 480 V to the adult heart without damaging the myocardium. The device weighed 120 kg and was used on two patients.37 Ironically, while Kouwenhoven spent decades studying defibrillation, he was beaten to the publication date by a Boston cardiologist, Paul Zoll.38 Kouwenhoven's enduring fame would come from his achievements in the development of another nonsurgical method of heart activation: external cardiac compression, the basis of CPR, which would play a great role in the spread of defibrillation procedure in subsequent years. For his work, Kouwenhoven would be awarded the American Medical Association Scientific Achievement Award in 1972 (Fig. 10).12'40

Zoll, the Harvard researcher who independently scooped Kouwenhoven on transthoracic AC defibrillation, came to defibrillation research from a different beginning: after working in cardiac surgery in the U.S. army during World War II, he came back to civilian practice and soon became fascinated by the case of a patient with recurrent Stokes-Adams attacks. Zoll started to perform experiments on external cardiac pacing and defibrillation in animals, and first used an external pacer in a patient in 1952. Although the prevailing medical opinion at

William Kouwenhoven Heart
Figure 10: Kouwenhoven defibrillator, 120 kg, William Kouwenhoven

the time held that external defibrillation would never work because the necessary electric current was believed to be so high that significant damage to the patient would be caused before it reached the heart, Zoll based his experiments on the same research from the 1930s as Kouwenhoven did, and also believed the prevailing opinion to be wrong. He had a model for human external defibrillation built by Electrodyne, successfully used it in 1955, and published the results in NEJM in 1956.38 Prohibitively large and heavy, the Electrodyne defibrillator, like its cousin made by Edison Electric, was only portable to the extent to which it could be wheeled into the emergency room, its most bulky component being a transformer that could convert the wall outlet supply to 1,000 V.12

These advances were being made at a time when a great surge was beginning in the development of lifesaving emergency methods and procedures. Claude Beck had declared that battling sudden cardiac death should be a national priority, and the idea proved popular; his associate Dr. David Leighninger famously stated that "many hearts die that are too good to die."39 Autopsy studies performed at the time showed that nearly 70% of sudden cardiac death cases showed no new pathology in the heart tissue, but had stopped due to electrical problems that could be fixed by electric pacing or defibrillation. At the same time, the development of quality prehospital care and intensive emergency procedures inspired greater interest of both the medical authorities and the general public; interest fueled funding and development; and these in turn generated results, which attracted further interest. Intensive care in nonmilitary hospitals developed toward the middle of the twentieth century, following along with advances in medical technology and surgery. It started with setting aside a specially monitored room for patients recovering from high-risk surgical operations. During the poliomyelitis epidemic in the 1950s, for instance, many hospitals designated new intensive care units for patients needing artificial or assisted respiration. The young specialty of cardiac surgery especially required nonstop monitoring of their patients by trained personnel and sensitive equipment. Therefore, as the new inventions of pacemakers, defibrillators, and cardioverters appeared, they could be immediately provided to cardiac patients undergoing intensive care at the hospital.5'12

Although civilian ambulance services began in some American cities in the 1900s as a transport service, most communities did not develop them until the 1940s. The modern emergency medical services system was established with the passage of the National Highway Safety Act in 1966, and professional standards for emergency medical technicians were first standardized in 1970.41 In the 1960s Kouwenhoven's closed-chest heart massage (now CPR) became standard practice for emergency rescue services, and in the 1970s the American Heart Association approved training laypersons in the technique.12 Thus, during the 1960s and 1970s, it became possible to imagine the fulfillment of the predictions of James Curry and Carl Wiggers: a patient would be kept alive by competent provision of oxygen to the tissues and defibrillated promptly by a portable defibrillator. Only one link in the chain was incomplete: a defibrillator that was truly portable and safe.

In the United States, that final link was created by Dr. Bernard Lown of Brigham and Women's Hospital in Boston. Lown used Zoll's apparatus to correct persistent ventricular tachycardia in a patient; the technique was successful initially, but the AC procedure later induced ventricular fibrillation. Finding alternating current to be thus unsuitable for cardioversion, Lown began investigating the possibility of using condenser discharges instead. In a 1962 JAMA paper, Lown, Amarasingham, and Neuman reported their success with the transthoracic treatment of nine ventricular tachycardia patients by monophasic DC shocks, where all patients reverted successfully with a single discharge. Commenting on their results, they cited previous work with DC defibrillation of human patients by both Gurvich and Peleska. They explained the difficulties encountered by other teams of scientists, Kouwenhoven and Milnor, Guyton and Satterfield, in trying to reproduce the results by lack of consistency in circuit design and current shape, noting that more research would be necessary.42 Already the team was investigating the possibilities, placing electrodes inside the chests of dogs and defibrillating them using different capacitor-inductor currents, in a resounding echo of earlier experiments. Seemingly unaware that the optimal DC waveform had already been discovered on the other side of the Iron Curtain, they wrote that "at the present time, there is no physiological basis for predicting the wave form which is optimal for defibrillation."43 Lown would pursue this line of research for many years, finally succeeding with the biphasic waveform model several years later.

The external DC defibrillator used by the Lown research team was first constructed in 1961 by the Hungarian engineer Barouh Berkovits and patented in the name of the American

Optical Company.44 Berkovits came to the United States after World War II and could have been familiar with research by Gurvich and Peleska on the other side of the Atlantic. Moreover, future model of Lown's "Cardioverter" was based on Gurvich's schematic.45'46 Berkovits then went on to solve the problem of pacemaker-induced ventricular fibrillation and to create the demand pacemaker in the 1960s-1970s.4

It was at that time that the subfield of defibrillation came to join paths with another emergent branch of cardiology research: cardioversion and cardiac pacing, the history of which is described elsewhere in this book. Defibrillators and pacemakers became sufficiently sophisticated to work together, sustaining heart rhythm inside the human body. The development of the implantable cardioverter-defibrillator (ICD) began with its inventor, Michel Mirowski, who came up with the idea of the device in the late 1960s after his mentor died of a heart arrhythmia, and he succeeded with the first human implantation in 1980.47'48 John Schuder published the idea of ICD at the same time, but he did not pursue its validation and development.49 Thus, Mirowski deserves most of the credit for ICD. A Polish Jew who left home at age 14 to escape the Nazis, Mirowski attended medical school in France, completed residency in Israel, and finished his cardiology fellowship in the United States. After living in Israel for several years, Mirowski returned to the United States in 1968 to become the coronary care director at Sinai Hospital in Baltimore and to conduct his research on the ICD as an alternative to surgery and drugs.50 This bold idea faced considerable opposition from the medical community of the early 1970s: prominent authorities in the field, including B. Lown, were concerned about the technical difficulties, less than clear indications, high costs, and possible dangers of the new technology, and skeptical that its use would be anything but very narrow.51

Nevertheless, Mirowski and his teem succeeded: the first human implant, employing a defibrillator device the size of a deck of cards and weighing 250 grams, was performed in 1980. Subsequent research would reduce the size and cost of the device, and the end of the twentieth century would witness the astounding boom of the technology, with hundreds of thousands of patients having implantable defibrillators worldwide.50 In 1982 the cardioversion function was fused with the internal defibrillator, and in 1985 the ICD received U.S. Food and Drug Administration approval. As it happened, this part of the chronology is where the waveform conundrum was finally solved in the West. The efficacy of an ICD is limited by the maximum energy supplied by the accompanying power source; in their quest for the minimal size of the device, the inventors of the ICD eventually chose the more effective biphasic waveform over the higher monophasic current used in transthoracic devices at the time.

It was thus that the biphasic waveform, as first described by Gurvich and used in external defibrillators in Russia,52 finally was incorporated into Western external defibrillators in the late 1990s. In fact, it was first proven to be more effective in implantable defibrillators, and only then made its remarkable comeback to external ones. This is another example of an eminent idea being circumvented for decades but finally winning the day due to superiority of design. With the final development of single-button automatic external defibrillators (AED),53 defibrillation became not only ubiquitous but even safe and available for use by laypersons. Popularized along with advanced CPR and first aid training, it has brought about far better odds of survival for victims of out-of-hospital cardiac arrest.

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