Heart Murmur – Dogs

A heart murmur is an abnormal sound produced by turbulent blood flow through the heart. In older dogs, heart murmurs are commonly due to degenerative valve disease, though other types of heart disease are possible.

A dog’s heart consists of four chambers and four valves. The valves control the forward direction of blood flow through the heart. In healthy dogs, these valves form tight seals when they close. As dogs age, their heart valves can become thickened and unable to close tightly, allowing blood to flow backward. This type of blood flow is heard as a murmur. Dilated cardiomyopathy (weakening of the heart muscle), congenital heart defects (birth defects), valve infections, and high blood pressure inside the lungs are other possible causes of heart murmurs.

While soft heart murmurs may be present for non-life-threatening reasons (termed flow or innocent murmurs), any abnormal heart sound should be further evaluated and monitored. Structural heart disease may be progressive, and over time, could result in heart failure or other life-threatening complications.

We recommend you make an appointment with a veterinary cardiologist or your primary care veterinarian to investigate your dog’s heart murmur.

If your dog shows any signs of difficulty breathing, distress, weakness, collapse, or exercise intolerance, please have him/her evaluated immediately, as these could be signs of a life-threatening condition.