The smartwatch is the next step in wearables tech, after the smartphone; but can a smartphone save a life? The Apple Watch is in its fourth generation with the Apple Watch 4. The Apple Watch has multiple improvements over its predecessor, being larger, with more storage space, but possibly most importantly, has a built-in electrocardiogram (ECG).

The Apple Watch 3 has recently made headlines in a controversial heart study showing its potential use as a screening tool for heart arrhythmias. The Apple Watch 3 is equipped with a set of optical heart sensors to detect your heart rate during exercise.

Theoretically, this means that you could use this device to detect heart arrhythmias in users. Heart arrhythmias affect about 2.7 million people in the US, and contribute to an estimated 130,000 deaths each year.

The issue with heart arrhythmia is that it is a largely asymptomatic disease. Many people are not aware that they have the disease during the early stages, which is where the Apple Watch comes in. By detecting the users’ heart rate, the watch should theoretically be able to detect spikes in the heart rate and alert the user appropriately.

In the Stanford-led study, users who reported arrhythmias had to apply a chest patch to verify the watches’ results to validate its use as a screening tool in future. While there was a relatively low rate of concurrence (around 30–40%), this shows the Apple Watch has some value as a tool to spot early-onset heart arrhythmia patients.

In an age of increasing tech and wearables adoption, tools like the Apple Watch may be useful to spot early-onset diseases that patients or GPs might otherwise miss, saving many lives in the process.