Clinical and Echocardiographic Findings in an Aged Population of Cavalier King Charles Spaniels

SIMPLE SUMMARY: Myxomatous mitral valve disease is the most common cardiac disease in dogs. Cavalier King Charles Spaniels are particularly susceptible to this disease, which generally appears earlier in life than other breeds, resulting, in some cases, in congestive heart failure and death. We hypothesised that within the elderly Cavalier King Charles Spaniels population, there is a sub-cohort of myxomatous mitral valve disease-affected dogs that do not have chamber enlargement. The objectives of the present study were to determine the prevalence and the degree of cardiac chamber enlargement associated with the disease in a population of aged Cavalier King Charles Spaniels, and to assess the effect of age, gender, and body weight on echocardiographic status. A total of 126 Cavalier King Charles Spaniels aged over eight years old were prospectively included in the study. On echocardiographic examination, 100% of them were diagnosed with myxomatous mitral valve disease; 55.6% of them presented chamber enlargement, and 44.4% did not. Age was significantly associated with the presence and the severity of cardiac chamber enlargement and mitral valve prolapse. Our results showed that a proportion of elderly Cavalier King Charles Spaniels with confirmed myxomatous mitral valve disease did not undergo advanced stages of this pathology. ABSTRACT: Myxomatous mitral valve disease (MMVD) is the most common cardiac disease in dogs. It varies from dogs without clinical signs to those developing left-sided congestive heart failure, leading to death. Cavalier King Charles Spaniels (CKCSs) are particularly susceptible to MMVD. We hypothesised that within the elderly CKCS population, there is a sub-cohort of MMVD-affected dogs that do not have cardiac remodelling. The objectives of the present study were (i) to determine the prevalence and the degree of cardiac remodelling associated with MMVD; and (ii) assess the effect of age, gender, and body weight on echocardiographic status in a population of aged CKCSs. A total of 126 CKCSs ≥ 8 years old were prospectively included. They all had a physical and echocardiographic examination. A systolic murmur was detected in 89% of dogs; the presence of clinical signs was reported in 19% of them; and echocardiographic evidence of MMVD was described in 100%. Despite the high prevalence, 44.4% of the dogs were clear of echocardiographic signs of cardiac remodelling. Age was significantly associated with the presence and severity of cardiac remodelling and mitral valve prolapse. Our results showed that a proportion of elderly CKCS with confirmed MMVD did not undergo advanced stages of this pathology.