Transferring between medical schools? (x-post /r/premed)

I posted on r/premed, but I guess it may be relevant here as well.

So here's my situation:

I've been out of school for about 3 years, but recently got into medical school. I'm psyched, as corporate America is most definitely not for me.

The catch is - it's a Caribbean medical school. Although it is in the 1st tier, I've heard enough negative things about coming out of the Caribbean in general, so I'm a bit cautious. I do not want to specialize in a specialty considered particularly "competitive" - I want to do cardiology - but obviously coming from abroad will put me at something of a disadvantage going forward.

My question is: what is the transfer process between medical schools like, particularly between Caribbean to US?

To confirm - I will be going to medical school in the Caribbean and I am not relying on transferring. I just want to be prepared and organized if I choose to try that route.

I ask because there is such sparse information available on the more conventional forums (like SDN). If someone who has gone through it is on here, I would love to hear a firsthand account.

Any feedback here is greatly appreciated.

Thanks in advance!