On World Heart Day, it's the perfect time to celebrate the history of the ECG, which stands as one of the greatest accomplishments of all time in the area of cardiovascular disease management.
The practice of medicine is constantly evolving, often at a pace that can cause innovations to become irrelevant quickly. Indeed, very few tools or tests that were utilized in the field more than 120 years ago are still in use today. This is part of what makes ECG—a tool that has stood the test of time—so fascinating.
The History of ECG
In 1887, British physiologist Augustus Waller applied a capillary electrometer,1 a device for detecting small rushes of electrical current, in his studies of the heart. This marks the first time a clinician was able to detect and record the cardiac electrical activity of a human being.
After the birth of the electrogram, the term used to describe the results of a cardiac electrical activity test changed, eventually transforming into "electrocardiogram," which was first coined in 1893 by Einthoven, who improved upon the electrometer. It was also Einthoven who introduced a correct formula that made it possible to describe, name, and distinguish between the five cardiac deflections: the P wave, the QRS complex, and the T wave (PQRST). In 1909, ECG was used to diagnose a clinical arrhythmia for the first time, and within a year, it was being used to describe the effects of heart attacks.
The Power of the Normal
In some respects, the history of the ECG can seem surreal, as the technology is still generally the same as it was a century ago, and it remains one of the most fundamental tools in the physician's kit. However, certain aspects of ECG have improved considerably over the years. For example, the first ECG machine,2 which weighed around 600 lbs, took five people to operate, hours to administer, and days to analyze. Now, devices are much smaller, with some ECG technologies even being miniaturized into tiny wearables, and it's among the first tools that emergency medical personnel use in ambulances, doctors' offices, and surgical centers.
This simple, quick, inexpensive way to synthesize the intricate electrical activity of the heart offers a wealth of information on the heart's normal state and pathological changes. A normal ECG can instantaneously rule out a whole host of cardiac diseases and electrolyte abnormalities, show chamber size and cardiac structure, and provide numerous other details about the current state of a heart.
A Guiding Light for Disease Management
Many of us take ECGs for granted now, but when you consider how much information they collect, it's easy to see that the ECG is truly one of the modern marvels of medicine.
In just seconds, an ECG provides critical information3 that can enable rapid decision-making in cases where patients present with chest pain. This information is crucial in determining which areas of the myocardium are at risk, what the diagnosis and prognosis are, what treatment the patient should undergo, and how the follow-up should be managed after procedures, such as percutaneous coronary intervention. Can you imagine managing the case of a chest pain patient without an ECG? Doing so would be impossible.
For a patient whose quality of life has suddenly plummeted due to an irregular heartbeat or sensation of palpitations, ECG can support diagnosis of an arrhythmia, show its acuity and urgency, and offer information on the patient's response to a therapy or intervention. When an arrhythmia requires ablation, the ECG is the guiding light for the hand of the electrophysiologist as they navigate the complex electrical pathways of the heart.
For a heart failure patient, ECG can show structural changes imposed by the cardiomyopathy and predict the benefit of cardiac resynchronization therapy and other medical interventions. ECG is also critical in screening competitive athletes for play, and for people with inherited channelopathies or other genetic diseases that could predispose them to fatal cardiac arrhythmias, ECG can be lifesaving.
The Future of ECG
Over the last 120 years, ECG has come a long way, but many of its clinical applications still remain the same. Yet the future of the ECG holds tremendous potential for new developments. Wearable ECG technology, including the Apple Watch, the Kardia device from AliveCor, and others, have provided many people with point-of-care ECG testing that they can incorporate into their daily lives to diagnose and manage cardiac disease.
For instance, wearables can enable population-level screening for arrhythmias, such as atrial fibrillation, which can be occult and underdiagnosed. They can also provide vital information on cardiovascular fitness and help guide exercise training and athletic conditioning.
Artificial intelligence combined with ECG technology can provide health systems with population-level information that could predict disease trends and evolution of cardiac diseases as well as support the detection of undiagnosed conditions, such as asymptomatic left ventricular systolic dysfunction.4 Wearable ECG vests can provide superior localization of cardiac ischemic to guide percutaneous coronary intervention by creating 3D ECGs.
The majority of heart conditions can be managed to prevent deaths—all it takes is awareness and a focus on diagnosing the condition early. ECG is here to stay and will continue to evolve as one of the best tools for diagnosis of heart disease. On this World Heart Day, let's all take a pledge to spread awareness of the risks of heart disease, learn more about the early warning signs and ask your doctor to use the power of ECG to the full extent!
References:
- AlGhatrif M, MD and Lindsay, J, MD. "A brief review: history to understand fundamentals of electrocardiography." Journal of Community Hospital Internal Medicine Perspectives. February 2012; 2(1). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3714093/
- Breakthroughs. "Flashback: The First ECG." https://www.breakthroughs.com/foundations-science/flashback-first-ecg
- Gorgels P and Wellens H. "The Electrocardiogram 102 Years After Einthoven." Journal of the American Heart Association. February 2004; 2004;109:562–564. https://www.ahajournals.org/doi/full/10.1161/01.CIR.0000117293.30403.8F
- Van Dam Peter, MD. "The future of the electrocardiogram." European Society of Cardiology. October 2019. https://www.escardio.org/Education/Digital-Health-and-Cardiology/Virtual-Journal/the-future-of-the-electrocardiogram
