Fig. 3. Doppler echocardiograms demonstrating valvular regurgitation. Recording from a SHHF-Cu- rat showing a black and white representation of a color Doppler mapped tricuspid regurgitant jet (*). The pulse-wave Doppler tracing (below) is characterized by a broad, holosystolic, turbulent flow pattern (a). Aortic regurgitation recorded from the left ventricular outflow tract of a LE-Cu- rat (b). The disturbed, holodiastolic signal (*) was recorded using pulsed-wave DE from a large angle which underestimates true maximal velocity. The triangular, normal systolic flow signal is also recorded. This rat also demonstrated mitral regurgitation (not pictured).