Why did Michael Jackson have a cardiologist he never had promblems with his heart?

I think Dr Murray was hired by AEG, why they felt the need to do that is something you would have to ask them. Michael has had doctors accompany him before though, he had one with him when Princess Diana died, his doctor was the one that told him.

AEG hired him because Michael apparently liked his holistic approach to healing and had a rapport with him.