J.S.
I have never heard of a dr doing an EKG prior to prescribing a stimulant ( my little brother had ADHD and was on ritalin for a short while). But he had to be taken off of it because he would get shortness of breath, chest pains, and a rapid heartbeat from it. Especially at night when the meds were wearing off those symptoms were strongest. They also made him sleepless. He would be exhausted but could not fall asleep. I remember hearing my mom in his room at night trying to help him go to sleep. He also had a massive loss in appetite and it was hard for my mother to get him to eat.
Maybe those are some things you could also discuss with his doctor. However on the plus side, the meds did work and kept him more attentive in what he was doing and helped him focus more.