Canine Valvular Heart Disease – NAVLE Study Guide

Overview and Clinical Importance

Valvular heart disease represents the most common category of acquired cardiovascular disease in dogs, accounting for approximately 75% of all canine heart disease cases. The most prevalent form is myxomatous mitral valve disease (MMVD), also known as degenerative valve disease, endocardiosis, or chronic valvular heart disease. Understanding the pathophysiology, diagnosis, staging, and treatment is essential for NAVLE success.

Figure 1 - Canine heart anatomy diagram showing all four cardiac valves - mitral, tricuspid, aortic, and pulmonic - with labeled chambers.

Myxomatous Mitral Valve Disease (MMVD)

Epidemiology and Breed Predisposition

MMVD is predominantly a disease of small to medium-sized dogs, with prevalence increasing markedly with age. Up to 85% of dogs in predisposed breeds show evidence of valve lesions by 13 years of age. The disease affects the mitral valve alone in approximately 60% of cases, both mitral and tricuspid in 30%, and tricuspid alone in less than 10%.