Hello and welcome to HCM.I carefully read your question and I understand your concern.But dont worry.I'll try to explain you something and give you some advises.
As you explain,my opinion as cardiologyst is that we are dealling whith a rhythm issue.You may feel
increased heart rate and this pounding feeling for different reasons.It may be a simple
tachycardia.It means that your heart beats over 100 for minute.Its normal range should be between 60-100 beat for minute. You may experience tachycardia for different reasons beginning from a simple emotional stres to different pathologys.You descript an
iron deficiency long ago.Sometimes this iron deficiency may lead to
anemia and this anemia can couse simple tachycardia.It is a compensatory mechanism of our body.
You may experience palpitations becouse of extrasistoles.This are escapet beats originating from different parts of the heart.They may have a lot of couses.So,if I was your treating doctor I will recommend you to do some examinations like a simple blood analysis to look for possible anemia,your thyroid hormons to exclude a
hyperthyroidism,electrocardiogram,echo cardiography and a holter monitoring to document your rhythm tendency.This for a simpme check up.At mean time avoid coffee and caffeine products becouse they rise your heart frequency.
I hope I was helpful.Wish you good health.