(A1) Two-dimensional right parasternal short axis view of the mitral valve and (A2) color Doppler showing medium mitral regurgitation in a BB dolphin. (B) Two-dimensional right parasternal short axis view of the left atrium and aorta in a BB dolphin. (C) Two-dimensional right parasternal short axis view of the left ventricle of a BB dolphin with thin left ventricular walls. (D1) Two-dimensional right parasternal short axis view of the tricuspid valve and (D2) color Doppler showing mild tricuspid regurgitation in a BB dolphin. Labels: MV = mitral valve, LV = left ventricle, LA = left atrium, Ao = aorta, AoV = aortic valve, RVOT = right ventricular outflow tract, PV = pulmonic valve, RV = right ventricle, MV = mitral valve, RA = right atrium, TV = tricuspid valve.