Which university is better?

I want to become a cardiac surgeon, and I want to get into a great university. At first I want to go to University of Chicago, but then I heard that Northwestern University is better for becoming a doctor or surgeon and U of C is better for research in medicine. Please can someone tell me which is better for me. Also, can you tell me what GPA and ACT score I should get to be accepted into either schools. Please and Thank you!