A 9-month-old 23.6-kg (51.9-lb) sexually intact female Golden Retriever was evaluated because of a heart murmur and tachycardia. On physical examination, a grade 5/6 right apical, coarse, band-shaped, pansystolic murmur was ausculted. The heart rate was 190 beats/min, and the rhythm was irregular. Severe left forelimb lameness was evident.
Echocardiography revealed marked dilation and hypertrophy of the right ventricle. Severely thickened tricuspid valve leaflets were present, resulting in severe valvular regurgitation consistent with tricuspid valve dysplasia (TVD). Electrocardiography was performed to evaluate the tachycardia. On the basis of orthopedic radiographic findings, a diagnosis of panosteitis was diagnosed. Pain was suspected