Myxomatous mitral valve disease

Chronic mitral valve insufficiency in a poodle dog, caused by a myxomatous valvular degeneration. LA - left atrium (partly resected), LV - left ventricle of the heart. Note the thickened, incongruent leaflets of the mitral valve

Doppler echocardiogram showing mitral valve regurgitation and MMVD.

Myxomatous mitral valve disease (MMVD), degenerative valvular heart disease, or endocardiosis is a noninflammatory disease of the heart valve where it loses collagen and elastin organization and overproduces glycosaminoglycans, becoming thickened, floppy, and coated with a thick gel. It can lead to valvular insufficiency and prolapse.

Myxomatous degeneration can also happen in the tricuspid valve, and less often in the aortic or pulmonic valves.

It has been described in dogs, and a similar disease in humans is a leading cause of heart valve replacement.

Diagnosis

• Clinical signs (cough, increased respiratory rate or effort)
• Heart murmur
• Thoracic radiographs
• Echocardiogram
• Electrocardiogram (EKG)

Treatment

Treatment depends on stage of the disease and clinical impressions. It can range from monitoring to drugs.

• Pimobendan (Vetmedin)
• ACE inhibitors
• Diet
• Furosemide (Lasix)
• Sildenafil (if pulmonary hypertension)
• Cough suppressants

References

• https://pmc.ncbi.nlm.nih.gov/articles/PMC7078050/
• https://pmc.ncbi.nlm.nih.gov/articles/PMC6524084/