A Look Back: 85 Years of Cardiac Pacing

The purpose of this article is to summarize the history of cardiac pacemakers, from its beginnings in the 1920s until present day. Technical and clinical challenges of pacemaker implantation will also be described. 

Introduction

The clinical relevance of pacemakers today is reflected by its widespread application in the fields of cardiology, cardiac surgery, and intensive care medicine. In the early 1960s, after the breakthrough development of implantable pacemakers, the preliminary estimate of global sales was roughly 10,000 units. By the early 1990s, sales had increased by more than 3000%, with more than 20 companies producing 350,000 pacemakers worldwide.¹ Given global demographic changes in the 21st century and cardiovascular disease being the most common cause of death in the Western world, the demand for pacemakers continued to increase. Today, more than 600,000 pacemakers are implanted every year. 

Recipients of cardiac pacemakers are predominantly patients older than 60 years; their average age is estimated to be around 75.5 years. However, patients of any age group may require pacemaker implantation. Special subgroups include newborns and children, who make up about 1% of all patients with cardiac pacemakers. Children will often depend on a pacemaker for the rest of their life.^2,3

Early Pacemaker History

The Italian biologist Luigi Galvani was presumably the first scientist to observe muscle contraction with the application of electrical current to the limbs of dead frogs in the early 1780s. Galvani published his observations in 1791.⁴ Since then, scientists and physicians have researched and applied electrical current for clinical use.

One of the first scientists to clinically use electrical current to stimulate heart contractions was the Australian physician Dr. Mark Cowley Lidwell, who applied electrical current to resuscitate newborns with asystole in the early 1920s.⁵ During the third session of the Australasian Medical Congress in 1929, he reported the first clinically successful use of electrical current for myocardial stimulation in a newborn:

“I designed some time ago a machine by means of which direct stimulation to the heart’s muscle may be applied. It was unknown, at first, what voltage was required. Dr. Briggs who was at the Crown Street Women’s Hospital, carried out experiments for me in stillborn infants. Voltage was used from 1.5 up to 120 and it was found that somewhere about 16 volts was the pressure required. The method was tried in two or three cases and was completely successful in the case of a stillborn infant, when everything else had been done to revive the child, artificial respiration, injections of pituitrin and adrenalin injected into the heart itself. After this had failed, the needle machine was plunged into the auricle and various voltages were tried with no result. The needle was then plunged into the ventricle, and the heart responded to each impulse. At the end of ten minutes the current was stopped and it was found that the heart would beat of its own accord. The child recovered completely and is now living and quite healthy.”⁶

Dr. Lidwell’s work was published in Anesthesia and Analgesia in 1930.⁷

Dr. Albert Hyman also worked on the development of a cardiac pacemaker in the late 1920s. He created a generator that was operated by a clock unit.⁸ His first model was named “artificial pacemaker” and was patented in 1930. Dr. Hyman designed three different models and tested them on a variety of animal experiments; however, there was no industrial interest in Dr. Hyman’s product in the United States. Dr. Hyman’s concept was used by the German company Siemens-Halske and tested by Dr. Siegfried Koeppen. Animal experiments, however, remained unsuccessful and the production was stopped.^1,9,10

The Golden Years of Pacemaker Development 

In 1948, William Bradford Shockley, John Bardeen and Walter Houser Brattain developed the transistor. Electrical switch units became significantly smaller. This technical breakthrough paved the way for a clinically applicable pacemaker. The 1950s and the early 1960s became the golden years of pacemaker development.^8,10

Dr. Paul Zoll was a cardiologist who built an external pacemaker that was first used in 1952. A 65-year-old patient was resuscitated and subsequently stimulated for over 50 hours until his own rhythm was sufficient for discharge from the hospital. 

Even though Dr. Zoll’s model did use a transistor, its clinical success was the final breakthrough for the industrial development of a cardiac pacemaker.¹¹

Clinical Challenges and the First Implantable Pacemaker

The clinical success of Dr. Zoll’s external pacemaker led to a greater interest and a breakthrough for pacemaker technology.¹² However, cardiac pacemakers in the early 1950s did not have built-in transistors, which resulted in a variety of disadvantages. Not only were they large and cumbersome, but they were not battery powered and relied on an electrical wall outlet. In addition, pacing leads were applied transcutaneously and often resulted in skin burns and infections.¹

Dr. C. Walton Lillehei and American engineer Earl Bakken took on these challenges and moved pacemaker technology and its clinical application forward. Dr. Lillehei was a cardiothoracic surgeon at the University of Minnesota. He had a particular interest in pediatric cardiac surgery. He observed that children often suffered from transient dysrhythmias after congenital cardiac surgery. In 1957, he sewed pacemaker leads onto the myocardial surface for the first time. The pacemaker leads were pulled through the skin and connected to an external pacemaker.^13,14 This application was successful and hence, for these patients, the disadvantages of transcutaneous pacing were resolved. Dr. Lillehei’s method has been used in thousands of adult and pediatric cardiac surgeries worldwide, and is virtually unchanged up to this day.

Nevertheless, the external pacemaker was still not battery powered and relied on an electrical wall outlet. After a power outage, Dr. Lillehei decided to contact Earl Bakken in order to have him develop a battery-powered cardiac pacemaker. Bakken, founder of Medtronic, developed a battery-powered pacemaker in the same year. It was also the first cardiac pacemaker built with a transistor. These small, portable and battery-powered pacemakers that stimulated the myocardium through direct contact were significant advancements. However, for patients who continued to be dependent on the pacemaker, one challenge remained. Infections and burns at the skin site where the leads came through were common issues, and only an implantable cardiac pacemaker could solve these issues.¹

In the late 1950s, the Swedish physician and engineer Dr. Rune Elmqvist from the company Elema-Schönander and the cardiac surgeon Dr. Åke Senning from the Karolinska Institute in Stockholm developed the first implantable pacemaker. The device weighed about 180 g and was still in its testing phase when the wife of Arne Larsson encouraged Senning to implant the pacemaker in her husband in 1958.^15,16 Larsson suffered from Stokes-Adams attacks, secondary to a viral myocarditis. The surgery was successful and in his lifetime, Larsson underwent 25 pacemaker changes. He outlived both his surgeon and his engineer, dying at age 86 from a malignant melanoma. During his lifetime, his pacemakers stimulated his heartbeat more than one billion times.^10,17

The Era of Transvenous Pacing

In order to avoid a thoracotomy, cardiac surgeon Dr. Seymour Furman developed the technique of transvenous pacemaker lead insertion. In 1959, he was able to thread a pacemaker lead through the basilic vein and secure the electrode to the endocardial part of the myocardium. At that time, he did not have implantable pacemakers readily available and used an external pacemaker.^18,19

Eventually, the transvenous technique was also applied to implantable pacemakers. In the early 1960s, Dr. Victor Parsonett succeeded in this technique in North America, while Dr. Hans Lagergren was in the forefront of this technique in Europe. Combining the advancement of implantable pacemakers with the transvenous access technique not only reduced skin burn and infections, but also avoided thoracotomy.^20,21 Even today, this technique remains the gold standard for the majority of patients who require pacemakers. Pediatric patients with complex congenital cardiac abnormalities are sometimes not candidates for transvenous pacemakers.

Technological Advancements

Considering that the first implantable pacemaker was about 180 g,^15,16 modern devices now weigh about 30 g and are the size of a matchbook. Longevity and efficiency have greatly improved.

One of the most important advancements that led to increased longevity is battery technology. The first implanted cardiac pacemaker used a nickel-cadmium battery. Later, zinc-mercury batteries were developed that functioned for over two years. Longevity was significantly improved when Wilson Greatbatch and his team invented the lithium iodine battery in 1972. This battery lasts for about 10 years, and is still commonly used by many manufacturers.²² 

Today, years after constant improvements in refining pacemaker size, longevity, and modes, the era of telemedicine has begun, and we are only one step away from the ubiquitous application of remote monitoring using implantable cardiac devices.^23,24

Conclusion

Eighty-five years ago, Lidwell first reported successful use of the cardiac pacemaker.^5-7 Since then, cardiac pacing has transformed from a concept to an integral part of high-tech bradyarrhythmic therapy. More than three million people worldwide live with various types of pacemakers, and more than 600,000 new pacemakers are implanted every year. Surgeons, cardiologists, and engineers have contributed greatly to advance the field of cardiac pacing and ultimately have helped save millions of lives.²² 

Editor’s Note: This article underwent peer review by one or more members of EP Lab Digest^®’s editorial board.

Disclosures: The authors have no conflicts of interest to report regarding the content herein.   

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