Why did my iwatch stop tracking my afib on feb 19? I have been wearing my watch! Help

Hi! Did you make sure you activated AFib history in the health app on iPhone? You also have to wear the Watch for the 12 hours like you said but for at least five days a week. These articles are helpful: Heart Health - Apple Support (CA) in the "Show AFib history" section and Track your AFib History with Apple Watch - Apple Support (CA) for more details. I hope this helps more! If not you should probably contact Apple support.

Hi! For Apple Watch to track Atrial Fibrillation, it needs to conduct an ECG or EKG (electrocardiogram). You need to initiate this manually, it does not do it in the background or automatically. First, open the ECG app, then start an ECG by holding your finger on the crown for 30 seconds. It will then tell you if you have signs of AFib or if your heart is beating normally, and you can track the results on your iPhone.