An 8-year old intact male yellow Labrador Retriever, was reevaluated by the Cardiology Service at Cornell University on August 8, 2008 to monitor the progression of tricuspid valve regurgitation caused by tricuspid valve dysplasia. Tricuspid valve dysplasia is an inherited abnormality of the tricuspid valve. It is defined as a congenital malformation of the tricuspid valve leaflets, chordae tendineae, or papillary muscles that usually results in tricuspid regurgitation1. Dogs are usually diagnosed as puppies and the condition progresses to right-sided heart failure within months to years after diagnosis. The most frequently affected canine breed is the Labrador Retriever.