My 8 year old son was on Strattera for about 4 months for ADHD. We noticed a real rapid heart rate, dh checked it here at home one night and it was 120. Took him back to the doctor and it was 125-126 somewhere in that neighborhood. So, the put him on an EKG machine. It was ok, strong and steady, just really fast. They changed his meds, thinking that it was caused from the Strattera as a rapid heart rate is a listed possible side affect. They told me to skip the next day and not give him anything that day, then start the new med the day after. The day I was due to start the new med, we checked his pulse before I gave it to him, and it was still 120. I didn't give the med to him, and called the doc again as soon as they opened. They said to bring him back in. So, we went back, again. It was still in the 120's that time. They put him on a holter monitor, which he will wear until Jan 6th. Sent us for an U/S of his heart the next day, and did blood work to check thyroid as thyroid issues are rampant in dh's family. The echo was ok, everything to and from his heart was ok, just showed it beating way too fast. The bloodwork was ok too. We are getting TONS of recordings. It will hold 3 recordings at a time then we have to call them in. Last Sat I called it in 11 times!!! Every morning when he gets up it's full. And sometimes I call it in when I get up, put it back on him, and then when he gets up an hour and half later, it's full again. They call it in at least twice every day at school. Even the days that they don't have PE and it's raining so they can't go outside at recess, they still have 2 call ins a day. We have an appointment this Tuesday with a Pediatric Cardiologist. I am worried sick. But at the same time I can't help but wonder if there was something serious wrong with him, wouldn't we have noticed this by now? I mean, he's 8 years old. Is it possible for us to not notice it for that long? What could be causing this?? Give me some ideas what me might be looking at here. Will he be able to get back on his ADHD med soon? I mean, not only is he driving me nuts, he's getting in trouble at school again, and his grades this week were HORRIBLE. He desperately needs that med. But every one of them I have looked at has the rapid heart rate as a possible side affect. I'm really worried and need someone to give me some ideas about what could be causing this. How serious is a rapid heart rate anyway? Is it that bad? I wouldn't think it would be as bad as a skipped beat, but what do I know? NOTHING....LOL Thanks in advance for any replies!!