I'm 80 years old and have A-Fib. But I take a beta blocker and calcium channel blocker everyday and my tests always show no irregular heartbeats.
I have a-fib also and two ablations, the second one worked.
I think it depends on your definition of irregular. I think the article includes a set pattern for each beat that is stretched out or compressed. Each beat includes a few peaks and dips. Whereas, for Afib, a beat is skipped or the pattern of each beat is changed. The rate gets so fast the the heart does not expand enough to allow it to fill up with blood and therefore can not pump much blood to the body.