What does my dog's heart murmur mean? - Mitral Valve Disease❤️
Updated: Nov 9, 2022
Dogs can have heart murmurs for lots of different reasons. Some can be innocent and some can mean there is something going on with your dog's heart. In this blog post, we'll meet one of our veterinary nurses and her dog with mitral valve disease and our vet Naomi will explain what heart murmurs can mean and what we can do about them.
Mitral Valve Disease
Mitral valve disease is the most common cause of a heart murmur in dogs. This disease is a progressive, age-related condition that causes the valve between the left atrium and left ventricle to change shape allowing blood to flow backward into the left atrium, this backflow through the valve causes the murmur which can be heard with a stethoscope. In a healthy heart, the valves close completely when the heart pumps, stopping any backflow of blood.
Over time this backflow of blood causes stretching and enlargement of the left atrium and fluid accumulation in the lung fields (pulmonary oedema), the murmur also becomes louder, and dogs may also begin to develop signs associated with heart disease including tiredness and exercise intolerance, increased respiratory rate and effort, coughing and sometimes fainting or collapsing episodes.
Affected animals are usually middle-aged to older dogs. It is most common in small to medium-sized breeds, especially the Cavalier King Charles Spaniel, dachshunds, terriers, chihuahuas, and miniature poodles.
The easiest way to assess whether a heart murmur is causing a problem for your dog is by performing a heart scan (echocardiography) to assess the flow over the mitral valve and measure the size and shape of your dog's heart chambers. This information enables us to start medication as early as possible to slow the changes in the size of your dog's heart and improve their heart function.