I suspect the answer will be 'piece of string', I wish I'd asked when I got it and will phone cardiology on Monday.
I thought my AF had disappeared again although my heart was still feeling unstable, but it came back at the Church fete 😬 I tried to tough it out but when I nearly collapsed off my chair (which would have landed me on the vicar's lap) I had to be taken home. The rate seems to be escalating, this time up to 160, so I'm looking forward to getting sorted out 😧