Management of preclinical mitral valve disease in dogs

Background: Myxomatous mitral valve disease (MMVD) is the most common heart disease in dogs. It is most common in small- and medium-sized breeds, with certain breeds, especially the Cavalier King Charles spaniel, being particularly over-represented. MMVD typically has a long preclinical phase and only a minority of affected dogs will eventually develop congestive heart failure (CHF); most dogs presenting to their veterinary surgeon with MMVD will, therefore, be in the preclinical phase. However, although, for most dogs, the disease is relatively benign, others will experience early onset, rapidly progressive disease (in which dogs might develop CHF at seven to eight years of age). Identification of these higher risk patients represents a significant clinical challenge. Treatment with pimobendan has been shown to delay the onset of CHF by an average of 15 months in dogs with evidence of eccentric hypertrophy (ie, left atrial and ventricular enlargement secondary to volume overload). Identification of the dogs most likely to benefit from treatment is therefore central to the effective management of preclinical MMVD.

Aim of the article: This article provides an overview of the diagnosis and management of preclinical MMVD. The aim is to help practitioners to effectively identify those patients most likely to benefit from treatment.