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ECG: What is it and why does it matter?

What's the deal with ECGs? And is there a difference between ECGs and EKGs?
February 10, 2022
apple watch series 6 review ecg electrocardiogram
Jimmy Westenberg / Android Authority

You may have heard of a feature called “ECG” — aka EKG — making its way onto wearables as of late. Devices like the Samsung Galaxy Watch 4, Apple Watch Series 7, Withings ScanWatch, and others are amongst several smartwatches that now come with an ECG sensor. We’ll explain what you need to know about ECG technology in consumer wearables.

What is ECG?

Short for electrocardiogram, an ECG is a test that measures the heart’s electrical activity.

With each beat, an electrical wave is sent through the heart. This causes it to contract and pump blood to the rest of the body. An ECG measures this electrical wave to help determine the health of the user’s heart.

It does this by measuring the amount of electrical activity in the heart and the time between heartbeats. This can help determine if the heart’s activity is normal, slow, fast, or irregular. It can also tell if parts of the heart are too large or overworked.

ECG vs. EKG: Is there a difference?

The only difference between ECG vs. EKG is the spelling of the abbreviation. ECG is an abbreviation for electrocardiogram or electrocardiograph — both English words — while EKG is an abbreviation for the German spelling of elektrokardiogramm. Functionally, electrocardiogram sensors and elektrokardiogramm sensors are the same.

How does ECG work?

This technology was exclusively used by medical professionals to evaluate patients in the past. A medical technician attaches ten adhesive electrode patches to a patient’s chest, arms, and legs through this process. Those patches connect the patient to a machine that interprets and displays the heart’s electrical patterns for a doctor to evaluate. The process is straightforward, completely painless, and should only take about ten minutes to complete.

So, if this way of performing an ECG is so simple, why do we need it on wearable technology? For starters, people with heart issues frequently need to monitor their heart health. If you can’t see your doctor right away, this can be difficult. Buying a wearable with an ECG sensor is a good way to keep an eye on things without setting up doctor appointments every other week.

Importantly, a wrist-based ECG is by no means a replacement for a professional medical ECG test. It may be helpful in some circumstances, but you should always consult your doctor regarding heart health.

Also read: The best heart rate monitors and watches

Are there any downsides to ECG watches?

withings scanwatch review taking an ecg recording fingers bezel
Jimmy Westenberg / Android Authority

Now that we’re seeing Fitbit, Apple, Withings, and other companies integrate ECG sensors into their wearables, why doesn’t every smartwatch come with one? There are a few factors as to why this is the case.

First, ECGs in consumer-grade wearables are certainly a niche feature. If you don’t have heart issues, you may not use your wearable’s ECG more than once! Companies that make wearables know this, which is why we don’t see ECGs tacked onto every single smartwatch. This will likely continue to be the case in the future.

Also, to sell a wearable with an ECG, the sensor first needs to receive medical clearance before going to market. ECGs need to be FDA certified in the US, while CE clearance needs to be granted in Europe. We’ve seen this approval process completely halt devices from launching in certain regions.

The Withings ScanWatch, which was announced in January 2020, only gained approval by the FDA for sale in the US in October 2021. This came months after it gained CE clearance in Europe.

Fitbit also ran into the issue with the Fitbit Sense. It actually launched the smartwatch on time in the US, though FDA clearance came a few months later. ECG functionality finally rolled out to the watch in October 2020.

Beyond government setbacks, some companies have imposed limitations on these sensors. Samsung, for instance, has made the Galaxy Watch 4’s ECG exclusive to those with Samsung phones. If you own another Android device, you won’t gain access to the sensor.

Additionally, it’s worth mentioning that not all ECG sensors are made equal. The Coros Vertix 2‘s sensor only records heart rate variability values, and there’s no way to view the device’s actual ECG data readouts.

Which wearables have ECG sensors?

A user holds a Fitbit Charge 5 face down showcasing the device's back sensors.
C. Scott Brown / Android Authority

As mentioned, a growing number of consumer-grade wearables now have ECG sensors. Here are some of our favorites:

Why should you consider buying an ECG watch?

Wrist-based ECG is primarily for people who need to evaluate their heart patterns regularly for whatever reason.

Maybe someone has a heart arrhythmia or atrial fibrillation (AFib) they need to monitor. Perhaps they’ve previously suffered from a heart attack and are now hoping their wearable can catch any irregularities before it’s too late. Maybe heart issues run in their family, and this is one easy step they can take to be proactive.

In the end, if you are reading this article because you didn’t know what an ECG was, you probably don’t need one on you at all times. But for some of you, this functionality could be revolutionary, even if to offer some peace of mind.