I've been going through the usual menopausal symptoms and one of them is a racing heart. It comes and goes and usually is associated with anxiety which is another symptom of peri/menopause. Not pleasant.
I was on HRT for about 7 years. I tried to wean off after about 5 years and the nightsweats were so bad that I couldn't sleep. I was afraid I'd fall asleep driving and my work performance suffered (brainfog). So, I went back on Premarin for about two more years. I weaned off again and the hotflashes/nightsweats are back. Still sleep deprived but I'm toughing it out. I've recently started using progesterone cream and also have Chinese Bitters/Fem-mate. (nasty tasting tincture) Still too soon to give a report. Anyway, I just wanted you to know that "racing heart" is a common side effect of menopause. I don't know the answer as to how to stop it.