What does atrial fibrillation look like in ekg or holter? if you are already taking beta blockers to suppress arrhythmia, does it mask af in ekg?

Irregular: Atrial fibrillation is irregularly irregular, (no pattern to the rhythm). Three issues with af: rate. The rate of untreated af is typically around 150 beats per minute which is too fast; secondly, whether it should be converted to a normal rhythm. And thirdly whether anticoagulation is needed. There are drugs to slow down the rate and drugs for conversion. A beta blocker would tend to slow down th.

Atrial: The key is in the atrial signal on the ecg. The normal discharge from the top chambers (atria) which is the "p" wave is now missing and there is either a coarse erratic signal from the top or sometimes even a near flat signal. This will make the bottom chamber signal also erratic/irregular but the key to the definition is in the signal from the top.