Palpitations from ritalin, long lasting

Patient: Helo Doctor, i am a 30 year old man and took ritalin for the first time during the month of december.After 2 weeks i stopped taking them and developped palpitations and chet pain.I went to the ER where they did an eloctrocardiogram but everthing seemed normal. Later i went to a pneumonoligst and he diagnosed asthma and gave me symbicort.After a week or so i stopped the symbicot and everything was fine. Then again i took ritalin for 2 days and palpitations came back 3 days later. they lasted for a week.Now, 1 and a half month later i took ritalin again for 4 days and i experience palpitations at night whe in bed or even now while at rest. my last doage was 2 days ago.I took 15mg of ritalin a day ( 10 and then 5 in the afternoon), this is supposed to be a really low dosage…My heart rate at rest today is 126 beats per minute. It eally starts to worry me but i can only see a cardioologst on monday!Is this a common complain?regardsEric