Are you someone who tries to determine whether an ECG trace is ‘irregularly irregular’ by drawing little dots on a piece of paper level with the R waves to see if they are evenly spaced? I’d done that for years until I read this fantastic suggestion, which I’ve been following for over a year now.
In the 1990s there was a popular series of posters and books called ‘Magic Eye‘. These contained a ‘random dot autostereogram‘ which appeared as a mish-mash of coloured dots, but when you stared at it for a while the illusion of a 3D image would emerge. They looked a bit like this (although this one won’t work at such reduced resolution):

Dr Broughton and colleagues from Cambridge, UK, discovered that this technique, which involves forcing a divergent gaze to get repeating patterns to appear to overlap, can be applied to an ECG trace.
Stereoviewing an ECG trace causes successive QRS complexes to visually overlap and produce a new image. As Broughton and colleagues point out:
“When achieved, this will lead to one of three outcomes. Entirely regular rhythms will ‘click’ into place as a new image at fixed depth. Rhythms with only mild irregularity may be stereoviewable, and if so, will appear to show successive QRS complexes at subtly varying depths. Rhythms with marked irregularity will not be stereoviewable, instead (in our experience) merely giving the viewer sore eyes after several failed viewing attempts.”
The authors assert that this can be applied to continuous ECG monitors, although unless you are really good at stereoviewing while moving your head/eyes horizontally, you should really freeze the trace on the screen first.
The ‘Magic Eye®’ method of rhythm assessment
Anaesthesia. 2012 Oct;67(10):1170-1