Can overdosing on adhd medication cause heart problems later on in life?

Unlikely: Very high doses of stimulants definitely can affect the heart, including the possibility of a heart attack. However, unless there is an actual heart attack, there should be no lasting effect of a single overdose on the heart. Such high doses, done repeatedly, can affect many organs of the body, including not only the heat but also the brain. So, prevent overdose--accidental or on purpose.