Are you stating that the DO residency literally matched *every* resident who wished to go into cardiology? This seems to be a bit of a stretch, unless a) the residency is very small and the fellowship is, comparatively, large; or b) a small fraction of each class opts for cardiology as a specialty (also unlikely). Even the top tier IM residency programs have some who do not match into cardiology, so I'd be very curious which program is laying claim to a 100% success rate in having every interested graduate of their program match into a cardiology fellowship.
Having gone through the NRMP (allopathic) cardiology match last year and been successful, I would recommend neither the DO residency program nor the community program with a university affiliation. Go for the gusto and apply to a large university based residency program. I'm not suggesting it necessarily makes you a better internist...it just exposes you to more opportunities key to having a higher statistical probability of matching, namely interaction with faculty for research opportunities and, most importantly, key letters of recommendation. This is the exact advice I give the DOs I interview for our residency, where I currently serve as Chief Resident.
