I found this Cavalier King Charles site with information on board certified cardiologists in the US and Canada. They are a breed with cardiac issues, so they would know the best in the field.
Board Certified Veterinary Cardiologists
Here are two in Alberta....don't know how far they are from you but they are board certified cardiologists:
Calgary
Dr. Michael R. O'Grady
CARE Centre Animal Hospital
7140 - 12th Street S.E.
Calgary AB T2H 2Y4
403-520-8387; 866-520-8387
info@carecentre.ca Care Centre > Home
Edmondton
Dr. Kimberley C. E. Hawkes
Guardian Veterinary Centre
5620 99th St. NW
Edmonton, AB T6E 1V2
780-436-5880
Emergency Veterinary Clinic & Specialty Animal Hospital - Guardian Veterinary Centre.