Before the invention of the pacemaker, humans were helpless in the face of sudden death and fainting caused by cardiac arrest. The invention of the pacemaker has opened up new means for human health. However, the original pacemaker is not a small device that we see today that can be implanted in patients. It is a big guy weighing 7.3 kilograms, and of course it cannot be installed in the body.
In 1932, the New York doctor Albert Hyman repeatedly found in the process of puncturing the heart for drug delivery that when the needle tip stimulates the right atrium, the atrial myocardium can be depolarized (the electric charge occurs when the cardiac muscle cells are “stimulated”. reversal) and shrink. This unexpected discovery led him and his engineer brother to start years of exploration. They began to design and manufacture an electrical pulse generator driven by a clockwork. They applied a bipolar puncture needle and inserted it through the intercostal space into the heart for pacing. They succeeded. The heart that had been in arrest for 15 minutes returned to normal beating. Of course, this bulky, generator-sized pacemaker is rather inconvenient to carry and can only be used for hospitalized patients. Hyman called it an “artificial pacemaker,” a term we use today and the first human pacemaker.
In the experiment, Heyman used a needle to puncture the right ventricle of the rabbit to conduct electrical stimulation to the ventricle, so that the heart that had been stopped for 15 minutes was re-beated and returned to normal heartbeat. Its function is to “resuscitate a stopped heart by intracardiac therapy” and can deliver 30, 60 or 120 pulses per minute. However, the design of having to crank it by hand every 6 minutes kept the invention from being accepted by the medical community. This clockwork-driven pulse generator was originally kept in Siemens in Germany, but unfortunately it was destroyed in World War II, leaving only a photo. However, this pioneering work by Heyman is enough to prove that electrical stimulation of some parts of the heart can effectively depolarize the myocardium and extend it to the entire heart, thus laying the foundation for the theory and practice of cardiac pacing.
A more practical small pacemaker that can be implanted in the body was invented in 1958 by the American Wilson Greatbatch (Wilson Greatbatch, 1919-2011). He runs an experiment at Cornell University to measure sheep ecology and animal behavior. One afternoon, when he was designing an oscillating device that could measure the heartbeat of animals, he grabbed a resistor in the work box and put it into the oscillating device, but the strange thing was that the electrode pulse sent by this oscillating device was 1 time per second, rather than a A device that measures the sound of the heartbeat. He looked at the resistor carefully, only to realize that it was the wrong one. This mistake brought him good luck, because the 1-second pulse of the electrodes was exactly what he had always wanted, which is the pulse rate of the pacemaker. He remembers having lunch in 1956 with two heart surgeons who said that if the nerves in the heart were out of order and couldn’t discharge regularly, the heart muscle wouldn’t relax and contract properly. One first aid method is to slam the heart with electrodes, but the equipment is large and cumbersome, and patients suffer from chest pains afterwards.
At the time, transistors had just been invented to replace bulky vacuum tubes, and batteries had dramatically improved in performance and size, so Glebazzi began designing small pacemakers that could be implanted in the body. The first device was tried on a dog and it worked very well. He continued to do animal experiments for another year, and began to work with Dr. William Chardack to apply it to humans in 1960. Their first patient lived an extra 18 months with a pacemaker implanted. Glebazzi then devoted himself to pacemaker research, especially the design of batteries. At that time, the most commonly used mercury battery on the market was Maroli’s mercury battery, which was composed of mercury oxide and zinc. Mercury batteries will release oxygen during the discharge process, which is easy to cause the device to rust, and the effect is not ideal. So he further developed a lithium battery, the anode of the lithium battery is lithium, and the cathode is an organic iodide. Lithium battery has high energy density, low self-consumption rate, small size, reliable and durable. Lithium batteries then became the standard energy source for pacemakers, making them smaller, more reliable and durable.
Glebazzi owned hundreds of patents in his lifetime, was inducted into the National Inventors Hall of Fame in 1986, and won the National Technology Innovation Award, the highest technology award in the United States, in 1990.
At the same time, the pace of development in the field of cardiac pacing technology in Europe can be described as equal. The most famous is the pacemaker “Three Musketeers”, they are surgeon Arko, engineer Neri&Hu and patient Larsen. Larson suffered from complete atrioventricular block and frequent cardiac arrest. At the age of 43, he was reborn because of pacemakers. He replaced 26 pacemakers in his life (the battery was very weak at that time, and the average lifespan was 2 years), lived and worked on a pacemaker for another 43 years, and died of cancer at the age of 86. In 1986, at the pacemaker academic seminar held in Monaco, the presidium of the conference awarded the “Pacemaker Honor Award” to these three people in recognition of their cooperation in promoting the development of pacemaker.
In recent years, pacemakers have evolved into multifunctional devices that can monitor and stimulate both the ventricle and atrium simultaneously, thereby increasing efficiency. The size of today’s pacemaker is about 2 cm, about 30 grams. Lithium battery life is 5-10 years. An estimated 5 million patients are currently equipped with pacemakers for Glibazil.
In 1984, the American Society of Professional Engineers named the pacemaker and semiconductor technology as the ten most outstanding inventions in the first half of the 20th century. Today, cardiac pacing technology is still developing rapidly, and many new functions and technologies come out every year to make it more perfect and benefit the wearer. With the continuous development of cell biology, molecular biology, genetic engineering and other related technologies, biological pacemakers that are more in line with human physiology have unlimited development prospects, and will certainly become the goal of people to treat bradyarrhythmias.
