Should A Doctor Be Consulted For Irregular Heart Beats?

Hi, should I be concerned that my 15 year old daughter is concerned about irregular heart beats that she has been experiencing the last several days? She says her heart beats fast at times but more importantly she is saying that her heart skips or stops for a sec and then starts back up. I know that her heart is not stopping but that is how she is describing it to me. I did manually take her pulse several times and found that her pulse does delay for a sec and then resumes as normal. The delay happens frequently but in no particular order. She has been on Sertaline (100mg) amitriptyline (100mg) and lithium (50mg) which she has been on for a year, She is in the process of getting off her meds and I have read that irregular heart beats are one of the side effects that can be serious. She has never complained until now of this. Should I take her to the Dr s or is this normal? Thanks