no, not necessarily. actually, arrhythmia is common in atrrial flutter and it's always present in atrial fibrillation
i thought what makes the difference between atrial flutter and atrial fibrillation is the rythm because in both pathologies "p" doesnot exist. besides, commonly the mecanism is " macro reentry" in atrial fibrillation what means regular crossing through AV node....unless this is uncommon case
You' re right, AF is usually regular since the AV node cannot conduct at the same rate as the atrial activity, and that's why the ecg usually shows a sort of a block of type 2:1, 3:1 or 4:1, but this block may also be variable and cause atrial flutter to appear as an irregular rhythm. The difference between those two pathologies is that, in atrial flutter, you find those big F waves, alternating with a frequency of 300-350/s, while in atrial fibrillation, there are smaller f waves, alternating with a frequency of 350-600/s.