A lot of people with fibromyalgia have comorbid conditions. Have you looked into POTS?
I had a major heart attack 2009. Had already been diagnosed in 1993 with fibro. And I didn't get diabetes 2 until a couple of years after the heart attack. Since then I have been through the regime of diabetes - at one stage on 75 units of insulin twice a day! Now I am on no insulin and no tablets - just ozempic once a week. This makes me virtually a diabetic in remission.
No issues affected my heart with my Fibromyalgia. However when I was on CELEBREX for a short time, that drug definitely did affect my heart. When I stopped taking the Celebrex, eventually my heart went back to normal.
I got diagnosed with an arrhythmia after I had fibromyalgia.
I also have type 2 diabetes and my cholesterol is higher than they want a diabetic’s to be. I do have a very mild mitral valve prolapse (congenital which can sometime co-occur with Fibromyalgia & my hear rate seems to be on the high side, while my sister has an atypical heart rhythm so thing in the SD node I believe. She also has fibromyalgia and a new diagnosis of Ehelors Danlos.