Endocardiosis in Dogs

Written by Tara Evans

Tara started her dream career in a mixed animal practice in Sussex in 2003. She qualified as a veterinary nurse in 2006 and continued to work in first opinion practice until she joined the Vita team in 2018. Her passion for the care and welfare of animals continues and couldn’t turn her back on veterinary nursing completely so continues to work regular shifts at a local first opinion practice.



Endocardiosis alters the physical structures of the heart valves due to an accumulation of fibrous tissue. This condition is inherited and degenerative. Symptoms vary depending on severity of disease. Once started, treatment will be lifelong.

What is endocardiosis?

Endocardiosis is also referred to as valve disease or insufficiency and occurs when abnormal tissue accumulates within the tricuspid or mitral heart valves (these ‘atrioventricular’ valves separate the atrial chambers from the ventricular chambers of the heart). This alters the physical structure of these valves, and makes them leaky, so the heart muscle needs to work harder to ensure adequate blood flow around the body.

What are the causes of endocardiosis in dogs?

The exact cause of endocardiosis is unknown, but it is likely to be a genetic condition as some dog breeds are more likely to develop this type of heart disease. Unfortunately, it is a degenerative condition, worsening over time. Although any dog can be affected, endocardiosis tends to affect dogs over the age of 10, but younger dogs can also be affected. Dog breeds predisposed to endocardiosis include Cavalier King Charles Spaniels, Poodles, Chihuahuas and Dachshunds.

What are the symptoms of endocardiosis in dogs?

Clinical signs will vary depending on the severity of the disease but can include a heart murmur, coughing, less keen to exercise, lethargy, weakness, a distended belly, faster or more laboured breathing, and fainting.

What happens if my dog has endocardiosis?

The vet will perform a clinical examination, and may suggest diagnostic tests such as blood samples, X-rays, and heart scans. While a cure is not possible, there are treatment options to help manage symptoms of the disease and slow progression. The recommended treatment plan will vary depending on severity of the disease, and will be continued through life with regular check-ups to monitor your pet’s health and adjust doses if necessary.

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