Pulsed Wave Doppler and Color Flow Doppler Evaluation in Healthy Dogs and Dogs with Cardiac Disease

Doppler echocardiography gives a physiological assessment of blood flow within the cardiac chambers, across valve orifices and in the great vessels. Pulsed wave Doppler can detect flow pattern in a very discrete region of simultaneously imaged 2-D echocardiographic plane. Twenty apparently healthy dogs and twenty affected dogs with dilated cardiomyopathy and mitral valve insufficiency ten each were selected for the study and subjected to detailed color flow and pulse wave Doppler study. In color flow Doppler studies a normal mitral and tricuspid flow were red in color as the flow is towards the transducer and when the nyquist limit exceeded it had a layers of blue superimposed on it. Aortic flow was seen as hues of blue and red and because of depth of the aorta nyquist limit was low and aliasing was commonly seen. In pulmonary flow the flow was usually blue in color as it was away from the transducer and total reversal of color was often seen as flow progress from high velocity during early systole to the lower velocities at the end of systole. In mitral valvular insufficiency two out often dogs showed jet occupying less than 20 per cent of atrium, three out of ten dogs showed jet occupying 20-50 per cent of atrium and five out of ten dogs showed jets occurring more than 50 per cent of atrium. In dilated cardiomyopathy mild to moderate jets were appreciated in four out of ten dogs in both mitral and tricuspid valves and two out of ten dogs showed mitral regurgitation alone.