Couldn’t pay me any amount of money to do a CCM fellowship. Make sure you know what you’re getting yourself into considering the 2 years of extra training (read: indentured servitude), and no real benefit if you’re considering a career in PP. CT/CCM is really only viable in an academic environment.
That said, CT fellowship was entirely worth it, especially if you go to a solid echo program with a focus on 3D and structural interventions in the cath lab, which is the future of the field. Being a strong CT anesthesiologist IMO makes you a better clinician in the OR than a CCM background. I say that from experience, working with both in a PP environment.
Get solid letters of rec from at least one of your cardiac attendings, do as well as you can on your ITE, have a reputation as a hard worker in your program and good things will come your way. CT fellowship is competitive these days. Get your application in when the SFMatch opens around the holidays of your CA-2 year, IIRC.