I find your comment quite interesting. I had an ablation procedure 9 years ago for my Afib and have not had any problems since until last week. I have stayed at home during Covid and exercised by walking the neighborhood (without a mask). I've been ordering my food in and not going to restaurants or anywhere else. Last week I needed some things from Sam's and since it had been more than a year since I had been in the store, I decided I needed to go myself. I wore a brand new KN95 mask and was in the store for a good 45 minutes. When I got home, I did not feel well. I took my blood pressure, and it was 141/85 with a heart rate of 120 so I knew I was in Afib. I propped myself up in bed and took 2 regular strength aspirin. The Afib lasted for about three hours. That's the only time I have worn a mask as I have not been anywhere. Therefore, based on your comment, I think it is quite possible that the mask may have caused your Afib. I made an appointment with my cardiologist for January 6th, and I will ask him about that then. Thanks for posting. I hope it was the mask because I don't want to go through Afib again.