Myxomatous mitral valve disease is the most common heart disease in dogs, particularly affecting small breeds, and requires careful monitoring and management to protect welfare.
In early stages, myxomatous mitral valve disease has minimal welfare impact, but as heart failure develops, dogs experience breathlessness, reduced exercise tolerance, disturbed sleep, and anxiety. Pulmonary oedema — fluid on the lungs — causes distress similar to drowning sensations. With appropriate medication (pimobendan, diuretics, ACE inhibitors), many dogs can have a good quality of life for months to years. However, the hereditary nature of the disease in Cavaliers reflects ongoing welfare problems with breed standards that have historically prioritised appearance over health. Responsible breeding using cardiac screening programmes offers hope for reducing disease prevalence in future generations.