It was well over four weeks since I had gotten COVID-19. Other than a sometimes lingering cough and a little fatigue, I felt better. The only issue was a nagging chest tightness. It first started as an occasional quick but mild discomfort. It steadily became constant, but never “painful.”
Trying not to be a physician but a patient, I dutifully went in for a simple blood test and an electrocardiogram. An electrocardiogram, or ECG, is commonly known as an EKG, which is the German derivative. I haven’t had an EKG in a long time. It’s such a simple machine, yet it gives so much information. Luckily for me, all was good; I just had some mild post-COVID effects.
The first real EKG machine was developed by British physiologist Augustus Desiré Waller in 1887. He would place electrodes on a patient’s chest and back, and the heart’s electrical pulses would then cause the mercury in several tubes to move. This image was projected onto a photographic plate (a flat sheet of metal), and a static image was recorded. This may call to mind images of a Dr. Frankenstein, but remember that the science was in its infancy. The Waller device was obviously not very accurate. He didn’t even recognize the clinical importance of his invention, according to the article “AD Waller and the Electrocardiogram, 1887,” published in the British Medical Journal.
While Waller missed the significance of his invention, others did not. His work was taken further by Willem Einthoven, a physiology professor at Leiden University in the Netherlands. Einthoven used a string galvanometer to conduct the first recording of the human electrocardiogram in 1905. A galvanometer is a device used for detecting and measuring small currents of voltage.
Einthoven’s machine weighed 600 pounds. Patients in the hospital were connected to his machine using a telephone wire from the laboratory to the patient, a distance of almost a mile. Patients had to place each hand in a saline-filled bucket, and their left leg in a solution-filled bucket. These buckets acted as electrodes to conduct the current. Einthoven coined the term electrocardiogram and won the Nobel Prize for physiology and medicine in 1924.
It was Sir Thomas Lewis of University College Hospital in London who recorded the first clinically irregular heartbeat. It soon became the “modern” modality to help differentiate a heart attack from simple chest pain.
What a difference a century makes. Today, we have what is commonly known as the 12-lead EKG. The 12 leads refer to the 12 vectors of electricity that are measured by a full EKG.
- Chest pain or discomfort
- Feeling weak, lightheaded, or faint
- Pain in the jaw, neck, or even back
- Pain in one or both shoulders or arms
- Shortness of breath
While cardiovascular disease is still our No. 1 killer, one thing that has changed significantly is what we know about the heart’s rhythm and what it means. And it’s all thanks to a 600-pound machine that can now fit in a wristwatch. Now if we could only learn to eat healthy foods and exercise more.
