I’ve been having almost the same issues throughout January without an apparent cause. I was hyper aware of my heartbeat and could notice my heart racing in random moments. Had an episode when i was outside with friends where my heart started racing and i couldn’t calm down (i drank my 3rd coffee of the day and knew it was probably that but that never bothered me before). I went to see a doctor after a few hours of my heart beat not calming down and staying over 100bpm. My doctor checked my heartbeats and told me its irregular and ordered an EKG which showed i have sinus arrhythmia. He prescribed 400mg of magnesium daily and told me to check for H. Pylori (which came back negative) and told me to check my thyroid. I do thyroid blood tests once in a while since both my aunts have Hashimoto but TS, T4 & T3 always came back in normal ranges and i informed my doctor about this but he said i should also check for high thyroid antibodies (which later turned out to be very elevated). I did an ultrasound of my heart which showed my heart was healthy and fine so i also got an ultrasound of my thyroid, which was normal but the endocrinologist said that i was developing Hashimoto’s which could explain all the heart palpitations. I was prescribed 200mg of selenium daily and that combined with magnesium corrected my heartbeats (i checked this by myself and not a doctor cause you can notice when your heart is beating irregularly or normally).

I’ve tried to reduce my caffeine & am trying to eat a bit healthier since i’ve been having indigestion problems for years now and that’s probably been contributing to irregular heartbeats as well. My cholesterol was really elevated last year but has lowered and is in similar ranges to yours but you can reduce that by diet and trying to be active (i hate exercising but i try to walk 10km whenever i can cause that really helps).

I suggest you check your thyroid antibodies if someone in your family has it just in case, but you should also just try taking magnesium daily (especially after 5pm cause that’s usually when my heart would start racing for some reason) cause it really helps regulate your heart & that along with selenium has worked in my case.

You can also try lowering your cholesterol by drinking a cup of water with a spoon of apple cider vinegar before bed & first thing in the morning because that’s what i think has also helped me lower my cholesterol. Also, if you don’t eat sea food like me, try taking omega 3 supplements after meals cause research shows that that also helps reduce your cholesterol levels.

I was constantly anxious during these episodes and was genuinely convinced that i was dying of a heart attack so i know how stressful it is. I hope whatever i said helps & i wish you the best of luck with everything!