The Mayo Clinic has an office with Representatives in Mexico to help you:
Services:

Help in scheduling appointments
General orientation to Mayo Clinic
Travel and lodging recommendations
Follow-up on previous visits to Mayo Clinic (medical reports, billing, insurance) and coordination of future visits
This office does not provide medical care.
https://www.mayoclinic.org/departments-centers/international/locations/mexico
The Mayo clinic is the best one in the entire world.

Also here is a list of great Cardiologists in Tijuana, Baja California (Mejico) with great experience. See here:
https://www.yelp.com/search?cflt=cardiology&find_loc=Tijuana%2C+Baja+California
Any other question, please let me know.