According to the Clevland Clinic :
Afib (atrial fibrillation) is an irregular heart rhythm (arrhythmia) that begins in the upper chambers (atria) of your heart. With Afib, your heart’s electrical system doesn’t work as it should. Instead of a steady, regular pattern of electrical impulses firing, many different impulses fire rapidly at the same time.
My heart has gone into AFIB four times that I know of. The first three times I underwent electrical cardioversion to reset my heart back to normal sinus rhythm. The last time, I had pulse-field ablation. For more information on this procedure, check out the Cleveland Clinic Article:
Pulsed-Field Ablation: A New, Highly Selective Catheter Ablation Method for Heart Arrhythmias
If you are in AFIB, or even think you are in AFIB, check with your cardiologist before you start running. In my case, I was getting light headed when I would stand after sitting for a while. I also noticed that I was exerting a lot more effort to try to run at my normal pace. When I went to the doctors, they took an ECG and told me that I was in AFIB.
As a runner, when my heart goes into afib, I slow down. My pace for training runs will go from a 10 minute pace to a 12 minute pace. I need to exert a lot more effort to try to run at a slower pace. The good news is, I checked with my cardiologist and he gave me the ok to run, even though I was in AFIB. I just needed to accept the fact that my times would be slower.
Even with slower times, I still get a good workout and I still feel better after I have run. It is also possible to run races. Again, you just need to reset expectations. You may not win or place in your division, but you will still get to enjoy that race with other runners. You will just be doing it at a different pace.
If you get the OK from your doctor to run with AFIB, RUN. Do not let your ego stop you from running just because you can’t run as fast as you use to.