During the era where developments in cardiac surgeries in children with congenital abnormalities, such as a hole between the two ventricles, sudden death by blockage in electrical conduction in the heart is one of the causes of catastrophic deaths.


Dr. Albert Hyman

Already, in 1932, well before the beginning of cardiac surgery, a physiologist named Albert Hyman had described the possibility of creating an artificial pacemaker.

This pacemaker has proven effective in animals. But, had he tried it in humans?

He did not share this information and everything remained blurry.



Dr. Paul Zoll

Dr. Paul Zoll, a graduate of Harvard Medical School, was interested in the development of an artificial pacemaker following the death of one of his patients; a 60-year-old woman with repeated loss of consciousness and a heart rate of 30 beats per minute.

When Dr. Zoll looked at the electrocardiogram, he noticed that the patient had a cardiac electrical conduction blockage. Electricity could not be transmitted from auricles to ventricles.


Defining moment

The death of this patient, whose heart was otherwise functioning normally, was an affront to Dr. Zoll.

An image of a wounded person at war starts the adventure

An image engraved in his memory of a patient during World War II came to his mind. The esophagus, this tube between the mouth and the stomach, touches the heart.


Image, imagination, intuition!

Using an electrode on a metal rod in the esophagus of an anesthetized dog, he was able to create an electrical stimulation of the heart.

His prototype is not practical ... He must find something else.


A second inspiration

A second inspiration comes from looking at a dog's chest. The triangular shape gives him the idea of ​​putting two electrodes on each side on the skin. It works!

The first attempt on a human takes place on his father’s neighbor. The man is 82 years old and faints repeatedly. The diagnosis is made, again, using an ECG.

He installs the electrodes on each side of the patient's chest.

According to Dr. Zoll, his pacemaker can have 3 possible outcomes:

• No effect

• Electrical stimulation of the heart

• Electrocution of the patient


He manages to induce electrical stimulation of the heart for 40 minutes, ending the loss of consciousness. The patient will then die, his heart having suffered too many intracardiac injections before this electrical stimulation.

Dr. Zoll still demonstrated 3 things:

• Electrical stimulation causes a cardiac contraction.

• Stimulation can be done on the skin without touching the heart.

• The human heart rate can be controlled by a machine.


Again, this equipment is obviously not practical. It is aimed at a clientele who must remain bedridden and can not move. Everything must be perfected.


Dr. Walt Lillehei, surgeon

In Minneapolis, Minnesota, surgeon Walt Lillehei is battling a cardiac electrical conduction blockage.




Heart blockage during surgery

To repair a hole between the two ventricles, resulting from a congenital malformation, requires a suture to close this hole. This suture is done at a strategic location for the electrical passage between the atria and the ventricles.

The closure of this hole leads to an electrical conduction blockage in nearly 10% of these procedures. Death is often unfortunately the result.

This blockage of electrical conduction is caused by the suture itself and by swelling due to inflammation, which is temporary.



He thinks of placing electrodes on the heart through a tunnel under the skin and continuing towards a battery. Nothing of the sort exists at this time.


A crucial encounter

He meets a young electrical engineer, Earl Bakken, and his brother-in-law. These two men set up a small business called Medtronic to repair medical electrical appliances. Dr. Zoll explains what he needs.


The transistor

It's the transistor revolution at this moment.

While browsing magazines, Earl Bakken discovers that the metronome, instrument to mark the tempo in music, uses the transistor. A metronome can give 60 shots per minute. By adding a mercury battery, the metronome can now give 60 electrical pulses per minute.

A few days later, Dr. Lillehey is confronted with heart blockage during surgery. He places two electrodes on the heart, brings the wires to the skin and connects them to the new device. From the start of the device, the heart rate returns to normal at 60 beats per minute!

Once again, the device is on the outside of the patient and, therefore, impractical. We must find better!


Dr. Wilson Greatbath

In Buffalo, NY, Dr. Wilson Greatbatch and engineer Andrew Gage are developing a pacemaker embedded under the skin.


Dr. Ake Senning

They are not the first to develop an internal pacemaker. In 1958, a Swedish, Arne Larsson, a 40-year-old engineer, receives the first internal pacemaker for heart blockage. Engineer Rune Elmqvist is the inventor.

The case is the size of a hockey puck.




This implantation in Mr. Larsson, a world first, was performed by Dr. Ake Senning.


Mr. Larsson died of melanoma in 2002. During his lifetime, he used 22 cases and 5 electrode systems.

This pacemaker, created by Rune Elmqvist, was acquired by St-Jude Medical Company, now Abbott, in January 2017. Dr. Walt Lillehei was the medical director after having ended his career as a surgeon.


From yesterday to today

Today, in the United States, more than 100,000 pacemakers are implanted annually. Nearly half a million Americans live with a cardiostimulator.