I second caregiver. It all depends on the extent of damage, something only your doctor knows. This would include how much effort you can put on your heart during exercise. You might want to ask your doctor about heart monitor watches he/she recommends. Good luck -
The pre-diabetes should have no relevance whatsoever. Exercise is indicated. As for the heart disease. It depends upon the degree of damage. In some cases there is a lot of damage. In other cases not much damage. You really need to consult your own physician for a recommendation.