Should you get an Apple Watch for Cardiac Health?

Apple Watch is a line of smartwatches produced by Apple inc. It incorporates fitness tracking, health-oriented capabilities, and wireless telecommunication, and integrates with iOS and other Apple products and services. Since its inception, it has been a revolutionary product.

 How useful is Apple watch ECG
Ask any person on the street ‘why are ECGs taken?’
The stock answer would be ‘to rule out a heart attack.’
But for that, you need 12 lead ECGs, which look like this,

12 lead E.C.G

In contrast, a bedside cardiac monitor shows the cardiac rhythm in 1, 2, or 3 monitoring leads, which tells us about the heart rhythm. Irregular heart rhythms can come from the top chambers of the heart (atria – eg. atrial fibrillation AF) or the lower chamber (ventricle – eg. Ventricular tachycardia

Cardiac Monitor Screen

The Apple Watch gives us a single lead cardiac rhythm, which can pick up cardiac arrhythmias like atrial fibrillation. But not a heart attack.
So bottom line, A Smartwatch doesn’t diagnose a heart attack, it is not meant to diagnose a Heart attack.

How good is it in accurately diagnosing arrhythmias?
The largest study with an apple watch was done in 2019 involving 419,297 patients, followed up for 8 months.
Only 0.5% of patients got a notification of AF (the expected incidence of AF in a healthy population is 3 to 4%). Of those with notification, a patch ECG was put on to see the accuracy of diagnosis. Only 34% of those (0.5% group) showing AF notification by Apple watch turned out to have real AF.
So even in the detection of AF, it has a low positive predictive value.
Despite all these, Apple watch has opened up a new era in wearable device-based diagnosis of heart rhythm abnormality and it is commendable.

Should you get one?
Buy one if you have a cardiac illness like arrhythmias (AF) or you are prone to it (Poor heart function, recovering from a heart attack, etc)