William B. Kouwenhoven: A Father of CPR

William B. Kouwenhoven

In 1947, a 14-year-old boy had to undergo surgery for a congenital condition called Pectus Excavatum, in which his chest bone had sunken into his chest. Claude Beck, MD, a prominent chest and heart surgeon, operated to repair the malformation. Just as Beck was closing the chest cavity at the end of the operation, the heart went into ventricular fibrillation while still under anesthesia.

Hurriedly, Beck reopened the chest and massaged the boy’s heart for 45-minutes. While the treatment kept blood moving through the heart, the organ had not begun pumping on its own. Beck had only one desperate option remaining to save the boy.

Assistants wheeled a device the size of a refrigerator into the operating room. It was a ventricular defibrillator still in research and development. Quickly, Beck switched the experimental device on and applied the attached paddles directly onto the boy’s naked heart. The surgeon placed an open electric shock to the heart. A moment later, the heart stuttered back to life and began to beat normally. Three hours later, the boy was awake and answering questions. He went on to full recovery. It was the first successful defibrillation of a human heart.1

Beck’s defibrillator was the culmination of 20-years of research, trial, and error launched by one man: William Bennet Kouwenhoven. Kouwenhoven would lead advancements in the technology for another 25 years in his dogged pursuit of saving lives through the application of electricity to the heart. He wasn’t even a medical doctor.

A Time of Change

William Bennet Kouwenhoven was born on January 13, 1886, in Brooklyn, New York, a descendant of one the earliest Dutch families to settle in New York. It was an exciting time for young Kouwenhoven. He grew up in a time of profound change in urban life in America. The discovery and introduction of electricity as a new power source had brought artificial lighting, motorized transportation, modern construction, increased production of food and improvements in health care. For instance, the EKG had become available in New York hospitals in 1906.

The spread of electricity throughout society and industry spurred Kouwenhoven to pursue the study of engineering at the Brooklyn Polytechnical Institute. He earned a Bachelor of Science in Engineering, then a Masters Degree in mechanical engineering at the school. He titled his thesis, The Effect of Electricity on Medicine. In 1913, he obtained his PhD in electrical engineering at the Karlsruhe Technische Hochschule in Germany.  

A year later, Johns Hopkins University established an engineering curriculum. The school invited Kouwenhoven to become the first electrical engineer in their new engineering program. Five years later, the curriculum became its own department. The University named Kouwenhoven an associate professor of electrical engineering. 

An Electrifying Problem

By the early 1920s, Americans were clamoring for the remarkable advances made possible with electricity. Lighting, cooking, communication with telephones, and radio were completely changing life in the home. Careers as electrician and lineman – who strung the electrical wires between locations – flourished.

With the increasing workload, the number of linemen suffering incidental low-intensity shocks increased. The shocks occasionally caused sudden death from ventricular fibrillation. The issue concerned Consolidated Edison, the power company in New York City, which initiated a study of the effect of electricity on the human body.

One of the universities involved in the research was Johns Hopkins, where, in 1928, Kouwenhoven would embrace the project that would become his life’s work.

A Dog’s Life

The year 1933 presented a turning point in the understanding of electricity’s effect on the heart. Researchers found through open-chest studies on dogs that an electrical shock could cause ventricular fibrillation. Efforts to stop the arrhythmia with IV medications were unsuccessful. Frustrations with the lack of progress were running high among researchers.

During one laboratory session at which Kouwenhoven was present, a dog was shocked into lethal heart dysrhythmia while its chest was open. Kouwenhoven shouted, “Shock him again!” The dog’s heart revived, and with it, the hope that medical professionals would one day be able to use electricity to revive human hearts in cardiac arrest. A prominent chest and heart surgeon named Claude Beck read about the success in a medical journal that year.2

Beck and Alfred Wiggers, a physiologist, subsequently developed a defibrillator of their design. In the early 1940s, they tried twice to apply electric shock to human hearts without success. Their subjects were older patients with diseased hearts who had developed ventricular fibrillation during their operations. Beck would go on in 1947 to save the life of the boy whose heart would stop during open-chest surgery.

Close to the Chest

In 1950, the Edison Electric Institute enlisted Kouwenhoven to lead a team to create a closed-chest defibrillator. Kouwenhoven was 65 years old when he started the project.

In 1955, Paul Zoll, MD, a Boston cardiologist, would deliver the first successful closed-chest defibrillation to a human. Zoll had already developed an external heart pacer to manage certain arrhythmias to restore normal sinus rhythm. He applied his experience with heart pacers to the application of electrical current to stop fibrillation of the heart. He developed an external defibrillator after extensive lab experiments on animals. He successfully performed the first successful closed-chest defibrillation of a human in August 1955.3

The Breath of Life

Kouwenhoven retired as the dean of electrical engineering at Johns Hopkins in 1954. He joined the Department of Surgery at the university under Alfred Blalock, MD, a renowned cardiac surgeon. The department provided Kouwenhoven with a lab to support the goal of delivering a portable defibrillator. One of the fruits of the research was the discovery of Cardiopulmonary Resuscitation (CPR). 

Kouwenhoven’s team included a young electrical engineering graduate student, Guy Knickerbocker. Knickerbocker observed that the femoral artery pressure of dogs in the lab increased when he tightened a strap around the chests of dogs that researchers were going to shock to induce ventricular fibrillation. The team concluded that chest compression was able to cause a pulse wave in the arteries that could circulate blood in the dog.

The discovery provided a necessary piece of the puzzle of how to revive the heart through electricity when no defibrillator was immediately available. 

Medical researchers had already learned that electrical defibrillation had to be applied to the heart immediately to be effective. For patients to survive, doctors had to apply the technique to hearts within 10 minutes of fibrillation. The brain and heart cease to function irreversibly in 10-to-12 minutes without oxygen. Oxygenation of the blood needs effective respiration. 

Anesthesiologists had already proven that expired air carried sufficient oxygen to maintain respiration. They had established that mouth-to-mouth respiration was enough to sustain a person who was not breathing for a limited time. Kouwenhoven’s team hypothesized that mouth-to-mouth respiration combined with the ability to maintain circulation by external cardiac massage would keep patients alive just long enough to transport them to a defibrillator or to bring a defibrillator to the patient.

The Johns Hopkins team used anesthetized dogs with induced ventricular fibrillation to prove the hypothesis. In 1957, they found that the fibrillated dogs could live for 30 minutes through chest compression and then electrical defibrillation. CPR had been developed under the direction of an electrical engineer! 

In the same year, Kouwenhoven rolled out a mobile defibrillator. Installed on a cart, the staff could move the 270-pound machine throughout the hospital to use the device. In 1957, Johns Hopkins had performed two successful defibrillations. In 1958, a resuscitation team at the university successfully revived 14 of 20 ventricular fibrillation cases. Kouwenhoven was 74 years old when he and members of his team went on a nationwide tour in 1960 to introduce this method to the medical profession.4

By 1961, Kouwenhoven and his team had managed the successful delivery of a 45-pound defibrillator that could fit in a small suitcase. In the same year, the Baltimore Fire Department began to develop a cardiac resuscitation program in the city based on the Kouwenhoven team’s technique and technology.

The remarkable accomplishment of William B Kouwenhoven, MD, is a tale of inspiration, serendipity, and relentless pursuit of a goal that has altered countless lives.5

Further Recognition

Dr. Kouwenhoven was a member of the AIEE (American Institute of Electrical Engineers) and served as vice president from 1931 to 1933.

Already a Fellow of the Institute in 1934, he became a member of the Board of Directors from 1935 to 1939. In 1962 this organization awarded Dr. Kouwenhoven the Edison Medal for “his inspiring leadership in education, for his contributions in the fields of electrical insulation, electrical measurements, and electrical science applied to medicine.”

He continued research at Johns Hopkins Medical School through the 1960s and in 1969 published a review article, “The Development of the Defibrillator” in the Annals of Internal Medicine, Vol 71. No.3. At the medical school graduation that year he received the first honorary medical degree ever awarded by Johns Hopkins School of Medicine.

He also was awarded the Hektoen Gold Medal by the American Medical Association.

During his long tenure at Johns Hopkins, he held the position of dean of the School of Engineering from 1938 to 1954. After retiring as dean, he was appointed an emeritus professor of surgery under the approval of Alfred Blalock, the chief of the Surgery Department. 

At the age of 87, he was awarded the Albert Lasker Award for Clinical Medical Research, America’s most prestigious biomedical prize. The award cited his “ageless genius” and acknowledged his landmark contributions.

He died in 1975 at the age of 89. An obituary in the New York Times lauded him for “developing the basic cardiac treatment devices and procedures used worldwide.”


1. Beck CS, Pritchard WH, Feil HS. Ventricular Fibrillation of Long Duration Abolished by Electric Shock. JAMA:1947 Dec 13; vol 135:985.

2. Hooker DR, Kouwenhoven WB, Longworthy OR. The Effect of Alternating Electric Current on the Heart. American Journal of Physiology. 1933; 103:444-454.

3. Zoll PM, Linenthal AJ, Gibson W, Paul MH, Norman CR. Termination of Ventricular Fibrillation in Man by Externally Applied Countershock. New England Journal of Medicine 1956; 254:727-32.

4. Kouwenhoven WB, Jude JR, Knickerbocker GG. Closed Chest Cardiac Massage. JAMA 1960;173:94-97.

5. Life In The Balance. Eisenberg, Mickey MD, PhD. Oxford University Press. 1997, pp 116-136; 186-192.

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