Best way I can describe it.... you feel like you may possibly go into AF or something the next time you exert yourself? Like you're fluttering but by the time you notice it, it's disappeared.
A bit like having indigestion, feeling full and being a few moments away from a massive belch?
No simmering here just lightning strikes and wham AF has arrived ....
Yes, lots of that lately, little quivers and thumps but of course as I have a monitor it's not quite succeeding!
Yes, thankfully havent felt that " simmering" feeling since march. It is almost always in the evening while watching TV, like indigestion but different. I know Im 100% heading into a fib when my jaw/ neck starts aching.
Yes definitely,like and kettle coming to boil and sometimes switching off before!
Oh yes! I now am very alert to the signs and am now noticing signs in my husband, I made him stop and rest to digest lunch yesterday when he was champing at the bit - to get going as he had so much to do!
I may have to rethink this 
my symptoms have changed since being on beta blockers.
I now know I was 'simmering' last night , while watching TV it felt like someone had grasped my shoulders and was shaking me gently with ripples going down my spine but my pulse rate was fine as was my heart . It didn't last more that a few moments.
I went to bed at 12 and woke to 'spend a penny' at 1am only to find the shaking had returned but was no longer gentle I was being shaken violently. My BP monitor confirmed 'irregular heart beat'.
I am finding these new symptoms quite confusing, my heart rate and pulse no longer rise dramatically and the symptoms are not as varied but still unpleasant. I managed to go back to sleep waking a couple of times to visit the loo and the shaking had gone by 6am.
This is exactly my experience. A fluttering or vibrating feeling, on waking I have an irregular heart beat which feels horrible, I feel light headed and weak.
I used to get a fluttery feeling in my upper chest/ throat and it disappeared after 15 or 20 seconds or so. that was my only sign I was going into AFIB. By the time I connect my garmin HR monitor the feeling was gone but my HR was 165 or similar!. When I was in AFIB i was asymptomatic - I could not feel the high HR.
We all lead a modern lifestyle which is slowly destroying our stamina and fitness. We need to move and slowly regain our health. Sitting is a modern curse, and it's effects are slow, insidious and deadly. Relax, nibble and die.
I get that feeling after particularly hard exercise. Whilst I hadn't had an episode of AF for 6 years til last night I do sometimes wake feeling aa if it might start.
In 11 years I have had AF onsets 4 times, all were on waking.
It seems for me when it actually happens, it happens during the night whilst I am sleeping.
How do you normally feel after an electrocardioversion?
How do you feel when in AF?
Do Flecainide and Bisoprolol make you feel worse?
What does AF feel like, and when should you go to a hospital?
When will I ever feel better
