The Apple Watch 4 is known to have an ECG feature that allows its users to monitor their heart rates. However, many cardiologists are skeptical about the app’s effects on its users. Some say users are at risk of overdiagnosis and other medical mistakes.

To access the ECG app on the Apple Watch 4, users must activate the app and hold their finger against the watch’s crown, as per Apple’s video tutorial. Hold the finger there for 30 seconds to complete the diagnosis. The app will then show if there are any symptoms and problems detected in the user’s body and if there’s any atrial fibrillation found.

Atrial fibrillation is a common sign of irregular heartbeat and could also be an early sign of stroke. The ECG app detects these signs and will notify the user if they have them.

While the app can detect the irregular patterns in the user’s body, specialists are still skeptical on how accurate the ECG feature’s diagnosis is. Cardiologists are worried that this technology that can easily be accessed by the masses could potentially increase overdiagnosis.

Overdiagnosing means people could be diagnosed wrongly and put into treatments that are unnecessary. The practice often happens when self-diagnosis is done and it does not help that the Apple Watch 4 ECG app gives users alerts about their health.

To properly check people if they have atrial fibrillation, they need to be strapped to a 12-lead ECG machine that is really capable of checking a person’s heart electrical activity. At best, the Apple Watch 4 app doesn’t fully read a person’s whole heart activity. While the app gives out immediate diagnosis, it also suggests users to immediately see their doctor if it has found something or felt something wrong within the wearer’s body.

As of late, cardiologists are also interested in gauging the efficiency of the Apple Watch 4 ECG app. Cardiologist Venk Murthy has collected some Twitter threads where experts have discussed the device and the app for their overall use.

At best, users should only use the Apple Watch 4 ECG app as a quick detection tool rather than relying on it like an actual doctor.

Apple Watch wash
Pictured: An Apple Watch is displayed in front of a new USD 1,699 Whirlpool All-In-One Washer and Dryer at the Whirlpool booth during CES 2018 at the Sands Expo and Convention Center on January 9, 2018 in Las Vegas, Nevada. Getty Images/Ethan Miller