Two Apple Watch features that can alert a user to dangerous heart conditions have been enabled for New Zealand users via two software updates (iOS 13.4 and watchOS 6.2, both now available to download).
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The first is an arrhythmia (irregular heartbeat) notification, which utilises an optical sensor that has been on every Apple Watch from the Series 1 onward.
The second is the option to run your own electrocardiogram (ECG) right from your wrist, by touching the crown (which contains electrodes) on an Apple Watch Series 4 or Series 5 - which completes an arm-to-chest-to-arm circuit, and electrical signals across the heart are measured.
The 30-second ECG reading classifies your heart rhythm as either AFib (irregular or atrial fibrillation), sinus rhythm (an indicator of normal rhythm), low or high heart rate or inconclusive. It is pitched the first do-it-yourself ECG of its type in the consumer sphere.
The ECG app saves results to a PDF file, which you can email to a doctor, or print out and take with you to a consultation. There's also integration with a number of online patient record systems.
Both tools gained FDA clearance in 2018, and the Irregular Rhythm Notification performed strongly in a Stanford University study that had people wear both Apple Watches and standard ECG patches for a week (of the participants that wore an Apple Watch and ECG patch at the same time, almost 80 per cent received the notification and showed AFib on the ECG patch, and 98 per cent received the notification and showed other clinically relevant arrhythmias on the ECG patch).
However, Apple stresses that its heart features are not diagnostic, or for monitoring. It frames them as screening tools that can help alert people to a range of possible conditions and provide them with more information to share with their GP or specialist. It also says its arrhythmia notification is not for people who have already been diagnosed; in that case, a person should work with whatever pharmaceutical or device solution that has been implemented by a medical professional.
The arrhythmia notification was not pitched as monitoring, in part, because it only runs every few hours. If it detects a possible problem, it will continuously test for a spell then alert the wearer if a possible issue is confirmed.
Apple said MedSafe approval was not required because its Watch is an example of a Class 1 external device rather than the implantable Class II.
Dr Sumbul Desai, Apple's vice-president of health, told the Herald that, while the Watch should not be considered a diagnostic tool, feedback from the medical community and users indicated an elevated heart rate "can be a good indicator of a number of conditions" including an impending fever or allergic reaction.
Fever is associated with Covid-19, but Desai says the new Apple Watch features are not being pitched for coronavirus checking.
The New York Times noted that the United States Preventive Services Task Force has issued a "D" recommendation for screening asymptomatic adults at low risk.
The group doesn't think there's enough evidence to recommend screening of adults at intermediate or high risk. It doesn't even think there's enough evidence to recommend screening adults 65 or older, who are at higher risk, for atrial fibrillation, the Times noted.
Desai responded that the over-65 prevalence might partly reflect that older people tended to be tested. Early data from Apple Watch heart tool users indicated that the prevalence of heart conditions in younger people could be more common than previously thought.
In July last year, for example, 30-year-old Phil Harrison, who was training for the Brighton Marathon in the UK, credited Apple Watch with saving his life. After experiencing, palpitations, he decided to test out the new ECG app on his Apple Watch Series 4 and received an Afib warning.
Harrison had experienced minor heart trouble before, but his doctor thought no further checkups were required, Runner's World reported. After the Apple Watch alert, Harrison learned that he needed open heart surgery to repair a valve in his heart. The surgery was successful. He said at the time he hoped to run the Brighton Marathon this year.
Desai also noted that all medical professionals agree that the sooner a heart condition is picked up, the better.
And she added that given the dire impact AFib can have on a person - it can lead to a stroke - all screening is worth it.