There is no acceptable limits for CT angio.but for ur age if CT angio is normal, u need not worry. If you get symptoms u can get a ecg done before directly moving towards repeat CT angio. Heart rate around 55-65 at rest is normal.. If u want to stop bp medicines, do a Ambulatory BP monitoring and take a Cardiologist consultation with the report.

Your parameters are within normal limits. There is no time cut off for validity of any test. The tests should be done according to your symptoms. If you have no symptoms no need to do any tests