Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.

Heart Failure Due to Valve Defect in Dogs

Atrioventricular Valve Endocardiosis in Dogs

Dogs’ hearts consist of four chambers: two atria (singular: atrium) and two ventricles. Between each pair of atria and ventricles are atrioventricular (AV) valves. The tricuspid valve is situated between the right atrium and right ventricle, while the mitral valve separates the left atrium and ventricle.

Endocardiosis is characterized by an excess of fibrous tissue developing in the atrioventricular valves, which adversely affects their structure and function. Over time, this leads to thickening, stiffening, and distortion of the AV valves, culminating in congestive heart failure (CHF). Consequently, the heart struggles to pump sufficient blood to the body, necessitating increased effort to meet its demands. This cardiac strain results in various complications, including ventricular stiffening due to augmented dilation. These changes ultimately precipitate heart failure and demise in afflicted dogs.

Typically, smaller breeds face a heightened risk. The following breeds exhibit a higher prevalence of AV valve endocardiosis: Chihuahuas, Maltese, Pomeranians, Cocker Spaniels, Pekingese, Cavalier King Charles Spaniels, Boston Terriers, Fox Terriers, Miniature Poodles, Miniature Schnauzers, Miniature Pinschers, Whippets, and Toy Poodles.

Given the chronic nature of this disease, eventual heart failure typically manifests in older dogs (over ten years old), although mild cardiac irregularities may be discernible in young animals. The incidence rate of AV endocardiosis is slightly higher in male dogs compared to females.

Symptoms and Types

The following symptoms are associated with atrioventricular valve endocardiosis. It’s important to note that the severity and frequency of these symptoms may vary depending on the severity of the disease:

  • Murmurs (abnormal heart sounds detectable by your veterinarian)
  • Coughing
  • Lethargy and weakness
  • Difficulty with exercise and intolerance to work
  • Labored breathing
  • Swelling of the abdomen
  • Orthopnea (difficulty breathing when lying down)
  • Cyanosis (bluish discoloration of the skin and mucous membranes)
  • Fainting
  • Loss of consciousness
  • Death

As the disease progresses, coughing, exercise intolerance, breathing difficulties, and other symptoms may worsen and occur more frequently.


The cause of atrioventricular valve endocardiosis remains obscure or unknown.


To diagnose atrioventricular valve endocardiosis in your dog, your veterinarian will first gather a comprehensive history of your pet’s health and the onset of symptoms. This history can provide valuable insights into which organs may be affected, particularly as heart failure impacts other bodily systems, such as the kidneys and liver. Following the history-taking, your veterinarian will conduct a thorough physical examination of your dog.

Laboratory testing is integral to the diagnostic process and will include complete blood tests, biochemical profiling, and urinalysis. These tests yield crucial information for a preliminary diagnosis and provide insights into the current status of the condition.

Further confirmation of the diagnosis may be achieved through imaging techniques such as X-rays and ultrasound, along with electrocardiography (ECG) and echocardiography to assess the heart’s electrical activity and structure. Color Doppler imaging is also used to evaluate blood flow. Together, these diagnostic tools offer vital information about the heart’s structure and function and the severity of the condition.

Modern advancements have streamlined the diagnostic process, enabling prompt identification of the condition so that treatment can commence promptly.


Atrioventricular valve endocardiosis is a progressive disease with no one-size-fits-all treatment approach. Treatment recommendations will be tailored to your dog’s current health status, the stage of disease progression, and any accompanying complications that require management to stabilize your pet. Your veterinarian will discuss all available treatment options with you to enable an informed decision-making process.

For some patients, minimal or no treatment may be necessary, with regular monitoring being sufficient. Others may require immediate emergency treatment upon admission. In more severe cases, extensive medical intervention or even surgical procedures may be recommended.

Medical treatment will target the underlying disease as well as any immediate complications requiring attention. Surgical intervention, such as valve replacement, may be considered for certain patients, although finding a skilled surgeon proficient in this specialized technique may be necessary.

Currently, surgical outcomes are not universally promising, but advancements in surgical techniques and expertise have contributed to improved success rates in this area of veterinary medicine.

Living and Management

Initially, your dog may require absolute cage rest, followed by gradual reintroduction to slow leash walks once their health stabilizes. It’s crucial to closely monitor your dog’s behavior and promptly report any unusual symptoms or behaviors to your veterinarian.

Given the progressive nature of atrioventricular valve endocardiosis, a high level of commitment and care is essential for successful management and treatment. Your veterinarian will provide a comprehensive plan for administering medications, managing exercise, implementing dietary changes, and other important home care instructions.

Dogs affected by this condition typically require an individualized sodium-restricted diet plan during treatment. Regular veterinary visits, particularly during the initial month of treatment, are necessary. These visits will involve standard laboratory tests, including radiographs and electrocardiograms (ECG), to assess your dog’s progress.

It’s important to familiarize yourself with the prescribed medications and adhere strictly to the recommended dosage and schedule. Follow your veterinarian’s guidance meticulously regarding your dog’s at-home health management. The long-term prognosis depends on various factors, including your dog’s age, the current status of the disease, any concurrent illnesses, and the effectiveness of management strategies.

Scroll to Top