[YorkieProud]

Originally Posted by Rhetts_mama

I'm so sorry about your pup. Your breeder sounds like every pet owners nightmare- one who not only knows very little about breeding, but doesn't care enough to take the time to learn.

Heart murmurs are the most common sign of heart disease in small dogs, but in no way do all (or even most) small dogs have them.

When a pathological heart murmur is found in a puppy, it's usually caused by a genetic defect. Older dogs can develop them later on, as valves start to weaken. A heart murmur it's self isn't a disease, it's a description of a the sound caused by turbulence in the blood flow. The murmur can be caused by the valves not opening and closing properly or an actual hole in an area of the heart.

Heart murmurs are graded on a scale of 1-6, with 6 being the loudest. The location of the murmur helps determine the underlying cause.

As for most dogs having them, in utero the blood obviously does not need to go to the lungs to be oxygenated, so the circulatory system has a duct that moves the blood away from the lungs and back out to the body (the ductus arteriosus). After deliver or whelping, when the first breaths are taken, the pressures in the lungs start the process of closing this duct. About 1:7 pups will have a problem known as patent ductus arteriosis, caused by duct opening and closing during the first few weeks. If left untreated, there is a high mortality rate the first year of life.

That's one of the reasons why those early vet checks are so important. It provides a baseline exam for a vet to watch the heart and note any changes in the presence/absence of murmurs and the grade and start treatment early if necessary.

A good breeder would be interested in knowing that one of his/her pups had a pathological murmur and adjust their breeding program based on the underlying disease.

Once again a very informative post. Thanks.

YorkieProud