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Predictors of the age of onset of chamber enlargement in Cavalier King Charles Spaniel dogs


To evaluate if young Cavalier King Charles Spaniels (CKCSs) with mild mitral regurgitation develop heart enlargement earlier than young CKCSs with no mitral regurgitation


Cavalier King Charles Spaniels get valvular heart disease at an earlier age than other breeds, and their heart disease often progresses more quickly. In this study, we want to find out if factors such as the age of onset of mitral regurgitation, diet, left atrial dimensions, and the shape of the mitral valve could be used as predictors of the age of onset of heart enlargement in affected CKCSs. We will start following Cavaliers while they’re still healthy and follow them over a long period of time. We hope our findings will allow veterinarians to provide better care for those dogs at higher risk, i.e. extend the quantity and quality of life of dogs with this condition.

Enrollment is by invitation only, based on participation in previous studies. We are currently not accepting new enrollments for this study.


  • Purebred Cavalier King Charles Spaniels who are >12 months of age
  • Otherwise healthy
  • No history of heart disease

Exclusion Criteria

  • Heart murmur louder than 2/6

Study Design

Dogs will undergo standard echocardiographic and physical examination to establish baseline measurements. Study exams typically take about an hour. Echocardiographic exams are a non-invasive, usually minimally stressful procedure and sedation will not be administered. Dogs will return for recheck examinations every 6 months until clinically-significant mitral valve disease develops, until the dog reaches 9 years of age, or until the end of the study period (2030), whichever comes first. For some dogs, it is possible that they will remain in the study for up to seven years. 


Enrolled dogs will receive, at no cost, a physical exam/office visit and complete echocardiographic examination. Six-month follow-up visits are also included for the duration of the dog’s enrollment in the study. All visits take place at the Veterinary Teaching Hospital in Blacksburg, VA.


Dr. Michele Borgarelli, Cardiology
Phone: 540-231-4621 | Email:

Mindy Quigley, Clinical Trials Coordinator
Office Phone: 540-231-1363 | Email:

If your query is urgent, please call the Small Animal Hospital at 540-231-4621.