Mine is low too. But normal. Check with your doc. Depends if you are symptomatic. But you won’t know when sleeping

The ‘% other’ is not a particularly useful number , in my opinion, it is simply saying that , in your case , 18.2% of the 20 second sections of the recording had some form of ectopic beat. That is not saying that 18.2% of the beats during the recording were ectopic, infact – with some ‘back of the fag packet’ maths, your data above is saying , to me, that anywhere between 18.1% and 0.6% of your heartbeats during that recording were marked as ‘other’ (which I believe means they were either earlier or later than expected).