I've been a faithful Samsung user for years. My household and family all have Apple, I refuse to switch. But the Galaxy 4 does not do the ECG Automatically or in your sleep Like the Apple watch. My doctor suggested I get the Apple watch to track if I have Afibs. What happened Samsung you are always a step ahead, am I gonna have to switch? If you don't have an update coming to address this I'll have no choice but to return my watch.
The apple watch doesn't actually do an ecg automatically either. It does monitor your hr OCCASIONALLY and look for irregularities. It used to be a feature on Samsung as well, but I can't seem to find it.
This is from an apple page: "The irregular rhythm notification feature on your Apple Watch will occasionally look at your heartbeat to check for an irregular rhythm that might be suggestive of atrial fibrillation (AFib)."
So if you want continuous monitoring for afib, Apple may not be your answer either. I'm an open heart surgery survivor and always have an eye out for Afib as well. I wish there was a better alternative but I don't know of one. Good Luck!
Go to apple s-u-p-p-o-r-t and search for "heart health notifications on your apple watch" to see what I'm referring to. It won't let me link it or mention it apparently, hence the dashes.