I've only seen DO's very occasionally in allopathic cardiology fellowships. However, I'm not sure if it's a function of having attended a DO school or more a function of not being able to get residency at the higher up academic allopathic med centers for IM. There's also the issue of USMLE scores. Some people go to DO schools because they've struggled with the MCAT, and those people tend to struggle more with USMLE also, which could be a problem for getting cards fellowship. Also, some DO students don't take the USMLE at all, which could be a problem.
I'm assuming DO hospitals have their own cardiology fellowships, but not sure how many there are.
I would think that with the expanding number of DO schools and the fact that in recent years some have moved closer to MD schools in terms of admissions stats and teaching/curriculum (while MD schools may have moved a bit in their direction too, in terms of philosophy and teaching), we may see more DO's in allopathic IM fellowships, but that's just a theory.
If you are going DO and want allopathic cards fellowship, I would suggest doing what MD grads do to try to get allo cards fellowship.
1) get into the best allopathic university IM residency you can
2) do cardiology research and get something published
3) try to get USMLE scores at or above the national average
4) get LOR's from cardiologists, hopefully ones with at least associate professor level and full prof is better if they know you/if you can get one
