Smartwatches get smarter with AF options but check out small print

It was only a matter of time before someone popped a single lead ECG into one of those wrist weightbelts called a smartwatch, or should that be dumbbell watch?

Top marks to Apple for being the first to do the obvious, an accolade given my personal anathema to Apple products evolved from a few trials and tribulations with iPhones, iPads and Macbooks.

It should be a substantial improvement over the plethora of heart rate detectors that litter both sports stores and rubbish dumps.

Quite how many health system hours have been wasted pursuing false positive tachycardia readings from fitbits and smartwatches remains unestablished, but for every media anecdote of a life being “saved” by a heart rate monitor, there must be 100 cases of worried-well fitness freaks plaguing GPs with errant heart rate traces.

Plus, I can add my own anecdote of having my rate over 180 prior to starting a rally stage due to the chest strap of my Garmin monitor jiggling around.

No matter what, this heralds the next mother-of-all-leaps-forward in digital health and the headache it will bring primary care, namely how will we cope with the atrial fibrillation epidemic and how do we manage intermittent AF.

The AF epidemic is obvious to any GP in practice more than 30 years. Our detection methods haven’t changed because ECGs have been around for yonks longer than this.

Sure, AF patients now live longer, witnessed by the reduction in stroke rates, but why is there so much AF? It’s not just ageing. Maybe it’s due to smoking cessation, PBA plastics, 1080, too much coffee, too much wine? I don’t know. Who does?

But one thing is for certain, AF rates will climb for this is a new, vastly more sensitive AF detector targeted at the wrong people.

How do we manage this coming epidemic of worried well iWatch users presenting irregularly irregular single lead traces on a 38 mm wide LED screen?

Other than having an indicator in Cornerstone for progressive reading glasses in every consulting room, we might be best to simply put NOACs (NOvel ANticoagulants) into the water supply.

More importantly where will this new breed of AFers fit into our CHADS/CHAD2Vs/whatever scoring system? We can label them as SCAFies (Sub Clinical Atrial Fibrillators) except our guidelines haven’t heard of them and neither has the clinical pathway that I use.

The Europeans have some guidance on the matter but it highlights uncertainty¹  for the key issues are that while SCAFies have an increased risk of stroke, the relationship between duration and frequency is uncertain.^2,3

There is some research around suggesting a duration of SCAF >24hours increases thromboembolic risk but in persons with a base CHADS2 score <1 the risk increase was negligible. Trouble is the study population, like most SCAFie studies, was not the likely iWatch user group or even a normal primary care population but rather in patients with pre-existing heart disease who either had an implanted pacemaker or Holter monitors.⁴

An interesting question is, given the US medicolegal paranoia, why is Apple bringing to market such a device without having the research to prove its safety and utility?

Marketers of similar ECG devices that hook onto smartphones have been quite prudent with their publicity but here we have the very big A not only promising this device, but also promoting its use for screening for AF, a big ask given the potential harms of AF management.

Mind you, I am sure Apple will address have figured out how to get patient informed consent prior to their putting their finger on the watch screen.

Now there is a but. Before you rush off down to your local Apple Store, read the not so fine print on the Apple website:

“Apple Watch Series 4 is capable of generating an ECG similar to a single-lead electrocardiogram. It’s a momentous achievement for a wearable device that can provide critical data for doctors and peace of mind for you.”

Proof that Apple has an excellent command of English.