Q: My 7-year-old, 20-pound mixed breed dog has a heart murmur. Her veterinarian thinks it’s due to chronic valve disease. What is this?
A: Each time a normal dog’s heart beats, it produces two sounds: lub-dub. A murmur is an extra sound, for example, a “swish,” as in lub-swish-dub.
In dogs under 45 pounds, the most common cause of heart murmurs is chronic valve disease. Ten percent of dogs have heart problems, 75 percent of which are chronic valve disease.
This disorder is most often inherited. Small-breed dogs are at increased risk, especially if they are male. The disease usually becomes apparent when the dog is middle-aged or older, but it can develop earlier in Cavalier King Charles Spaniels….