Apple claims its new Watch Series 4 can perform an ECG or electrocardiogram. But can it? And should it?

An ECG is a non-invasive way in which a medical professional can detect issues with the heart by checking its activity and rhythm. It involves electrodes placed on the skin. The Apple Watch has electrodes within the digital crown and the sapphire crystal back. The Apple Watch Series 4 will have an ECG app when the feature launches in the US later this year. 

According to the NHS, an ECG is designed to investigate beyond chest pain or palpitations and is usually “requested by a heart specialist (cardiologist) or any doctor who thinks you might have a problem with your heart, including your GP”.

Apple’s Jeff Williams may have said “this is the first ECG product offered over the counter, directly to consumers” during yesterday’s keynote but you have to ask why that is. It’s not usually a test for the home. Is Apple treading where it shouldn’t?

Should Apple give people the ability to do an ECG at home? 

Apple has clearly been encouraged by the Apple Watch’s various successes as a personal medical device – indeed, it’s done a better job at this than any other device before it. The detection of high heart rates has been especially popular and there have been a few cases where the Apple Watch has probably saved lives because it has prompted people to seek medical help.

Ivor Benjamin, president of the American Heart Association was on stage with Apple. "In my experience, people often report symptoms that are absent during their medical visits,” he said, adding "[this] is game-changing, especially when evaluating atrial fibrillation - an irregular and rapid heart rate that can increase a person’s risk of stroke, heart failure and other heart-related complications".

Atrial fibrillation (or Afib/AF) is where the upper chambers of the heart beat irregularly. There is a higher risk of stroke and heart failure.

Apple Watch EKG has been officially cleared for use

The American Food and Drugs Association (FDA) – the equivalent of the snappily-named UK Medicines & Healthcare products Regulatory Agency – has cleared or classified the device for use. Note that this does not mean “approved”, which requires much more testing. It's worth noting that the US refers to as an ECG as an EKG (from the German elektrokardiogramm), apparently to remove confusion with EEG in hospitals. 

According to Apple’s own press release, the watch has “an electrical heart rate sensor that can take an electrocardiogram (ECG) using the new ECG app, which has been granted a De Novo classification by the FDA and is coming later this year to the US first.

The De Novo classification is for “novel medical devices” that are "not substantially equivalent" – that means, essentially, that this is a totally unprecedented product. There has, however, previously been an accessory ECG device for the Apple Watch that was also cleared by the FDA.

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But what are the risks? 

Digging into the actual FDA clearance document there are a few caveats not least that “the ECG app is not intended for use by people under 22 years old [or…] individuals previously diagnosed with AFib”. You also need to be still for the ECG to work – “these data are only captured when the user is still.”

Equally “it is not intended to provide a notification on every episode of irregular rhythm suggestive of AFib and the absence of a notification is not intended to indicate no disease process is present” – so it’s a guide, not a 99.9 percent accurate test.

That’s key because some will feel completely assured by the ECG app and not seek appropriate care: “Over-reliance on device output leading to: failure to seek treatment despite acute symptoms or discontinuing or modifying treatment for chronic heart condition”.

The FDA ruling also points out that “false positive resulting in additional unnecessary medical procedures” could be an issue with the device, resulting in people going for actual ECGs that don’t need to happen.

No substitute for professional medical care

And naturally the documentation refers to the device not being a substitute for actual medical care. “The user is not intended to interpret or take clinical action based on the device output without consultation of a qualified healthcare professional.”

And furthermore “the feature is not intended to replace traditional methods of diagnosis or treatment”.

According to STAT, Apple tested more than 580 people, half of whom had atrial fibrillation. The ECG app was unable to read about 10 percent of the subjects but for the others it “was very accurate: It caught more than 98 percent of people with atrial fibrillation, and correctly told people that they didn’t have the condition 99.6 percent of the time.”

Apple has also carried out another substantial involving the accuracy of Apple Watch’s heart data – the Apple Heart Study with Stanford University.

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Is Apple Watch ECG a positive move? 

But these caveats shouldn’t take away from this being a pretty important step for consumer awareness of potentially fatal conditions. For people who have occasional symptoms, it could prevent some from having to use heath agency-administered devices to monitor their heart to prove there is an issue. 

And as a first step towards seeking medical help it's certainly a move in the right direction. In a statement, FDA Commissioner Scott Gottlieb MD was broadly positive about the device “The FDA worked closely with the company as they developed and tested these software products, which may help millions of users identify health concerns more quickly.

“Health care products on ubiquitous devices, like smart watches, may help users seek treatment earlier and will truly empower them with more information about their health.”