It is a chronic, degenerative disease of the heart valves. The valve flaps may appear 'lumpy', thickened, and fibrous; consequently, with these abnormalities the valves may 'leak'. Tendinous chords (chordae tendineae) or heart strings, which connect the papillary muscles to the tricuspid valve and the mitral valve inside the heart may also be involved. If so, they may become inelastic and can break, causing immediate consequences to the patient. The mitral valve, located between the left atrium and the left ventricle, is the most frequently affected .

Animation of the anatomy of the heart and operation of blood circulation:

Animation of the evolution of a endocardiosis mitral valve:

Hence, if these changes occur, the patient's valve may not be tight when closed, allowing blood to flow back into the atrium. Since this will then occur at each contraction of the heart, blood flowing against the prevailing current will create what your veterinarian hears as a 'heart murmur'. Murmurs are usually graded 1 - 6. If a murmur can be felt on the side of the chest, this is called a 'thrill', and it can usually only be felt with a grade 4 murmur, or higher.

(Some mild murmurs actually may be 'innocent' and have no pathological implications.)

Animation of heart failure with comparison between a normal valve and a valve that is not completely closed:

What are the breeds affected by this disease?

Cardiac valvular disease is a commonly identified condition.

It particularly affects small breeds of dogs especially those over 6 years of age. Some breeds are more likely to be involved than others:

  • Poodle
  • Chihuahua
  • Dachshund
  • Whippet
  • Yorkshire Terrier
  • Cavalier King Charles Spaniels (in which the disease is particularly common, appears much earlier and progresses faster).

How will I be able to detect this disease?

There is no outward sign characteristic of endocardiosis, unless a thrill can be palpated.

Usually it is during a routine consultation that your veterinarian first hears a cardiac murmur while doing a physical examination on your pet. This discovery may lead to a variety of more or less specialized tests to identify the specifics of the condition causing the murmur, and estimate the potential severity of its consequences on the functioning of the heart in the inpidual patient. Dependent on these results, medication to support the functioning of the heart may be needed

In more advanced cases, the first symptoms to appear may be nonspecific fatigue, more or less pronounced, especially when exercising, plus or minus a moist cough. Later, and as severity progresses, the pet may exhibit syncope (fainting), ascites (fluid causing a bloated abdomen), and difficulty breathing.

How will my vet diagnose endocardiosis?

The first step is a thorough clinical examination of cardiovascular function. Your veterinarian may recommend an ECG, or chest radiography or echocardiography (cardiac ultrasound), all of which are useful to highlight heart deformities, as well as to check for such pulmonary complications as edema (fluid in the lungs).

Animation showing an ultrasound endocardiosis dogs:

Is there a treatment?

There is no specific treatment for endocardiosis itself, but typically, your veterinarian will prescribe drugs to slow the progression of heart failure that inevitably results. Special (salt- restricted) diets are also helpful.

If you have questions and you'd like to reach out to us, you can call us directly at (925) 744-6421, or you can email us at [email protected].