What it is
Each time the heart beats, the mitral valve should close tightly so that blood moves forward into the body rather than back into the left atrium. As the leaflets thicken and sag, a little blood leaks back with every beat. The heart makes up for it by working harder and growing larger, so for a long time the dog can seem completely well.
The disease is linked to age and to inherited factors. When the heart can no longer keep up, fluid can build up in the lungs, which is called congestive heart failure.
At home, it is worth counting your dog's breaths while it sleeps: breathing that gets faster than its normal resting rate can be the first sign of fluid on the lungs, and your vet can tell you what rate is normal. Let your dog set the pace on walks, keep it out of the heat and at a healthy weight.
Signs you may notice
- Tires sooner on walks
- Coughing, especially at night
- Faster breathing while asleep
- Restless at night
- Fainting or collapse
You may notice the dog tiring sooner on walks, coughing, especially at night or after waking, or breathing faster than before while sleeping peacefully. Suddenly laboured breathing or fainting is a sign to see a vet immediately.
When to see a vet
Book a visit if your dog tires more easily, coughs or breathes faster at rest. If it struggles to breathe, has pale or bluish gums or faints, a vet is needed immediately.
This is general information, not veterinary advice. For your own dog's health, tests and treatment, see a vet.