you have to pass the ABIM medicine boards before you can sit for the cardiology general board exam. So the answer to your first questio is "yes". However, in 10 years when you have to retake the cardiology board certification exam, you don't have to keep up your board certification in IM. You only are required to be board certified in IM the FIRST time you take the cardiology boards. At least that is how it is for now.
Yes, there are separate board exams for EP and interventional.
