Cardiac Disease in Bernese Mountain Dogs: What to Screen and When

In the first year the question is congenital. Some large breeds are born with a narrowing below the aortic valve, which forces the heart to push against a fixed obstruction from birth. It is heard as a murmur at a puppy examination, and it matters because affected dogs can faint or die suddenly during exertion. This is why a murmur in a Bernese puppy should be rechecked rather than assumed innocent, and why any fainting in a young dog is investigated urgently.

From two to six the question shifts to muscle. Adult-onset heart muscle disease in large breeds has a long silent phase during which the chambers enlarge and the pumping strength falls with no outward sign at all. A stethoscope may hear nothing. This is the stage where owners of at-risk large breeds sometimes elect a baseline scan, and where any drop in stamina should be taken seriously rather than attributed to the dog maturing.

From six onward, which is senior in a breed living seven to ten years, the question becomes broader. Rhythm disturbances, valve changes, and disease of the sac around the heart all enter the picture, and in this breed a mass in the chest or around the heart has to be on the list because cancer is on the breed's documented health record. An annual or twice-yearly examination with a proper listen, plus attention to breathing rate and exercise tolerance, is the practical answer.

What runs through all three stages is the home measurement your vet will thank you for: the sleeping breathing rate. Count the rise and fall of the chest for thirty seconds while your dog sleeps, double it, and record it. A rate that has climbed consistently above its own usual baseline is one of the earliest signs of fluid backing up, and it is free.