if u r young,it is HIGHLY,HIGHLY UNLIKELY that u have a heart condition.do u drink a lot of caffeinated beverages?eat chocolate?that can give rapid heart rates.do u worry a lot,feel tense-anxiety disorders and panic attacks can make heart rate very fast,and u feel like u cant breathe or like ur dying.(ur not,it just feels that way)are u in ur late 30 s or over?hormonal fluctuations due to onset of perimenopause can cause heart racing and palpitations-very common in women this age.check for anemia,check for thyroid problems,both common in women and both can result in racing heart rate.the condition is most likely benign,but u do want to discover the cause,and get treatment if need be.see ur dr and discuss ur symptoms.one more thing-are u strictly dieting?eating disorders can have serious heart effects,so if u are having problems with eating disorder,u will need to talk about this,too.in most people,i will venture to guess from experience,the cause is usually too much caffeine or anxiety.im not downplaying the possibility of actual heart disease,but generally,it isnt the case unless u have a congenital abnormality of the heart-or u are maybe,50 or over.good luck,hope this helps!