Welcome! My name isXXXXX am a UC Davis graduate, and currently, a Medical Director of a veterinary hospital.
I am sorry to hear about this concern for Barny.
I have a Cavalier myself, and unfortunately, I lost my other Cavalier of 10 years of age 1 month ago due to severe heart disease
With this type of breathing you are describing, it is critical to get into an emergency vet. I am greatly concerned about a serious lung problem or a complication from congestive heart failure.
Very sorry to hear Barny is not doing well. With a breathing issue, at this age, and for this breed, I would get him into an emergency vet. It's worth the trip.
Please let me know if there is anything I did not cover for you. I hope that information has been helpful.
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