- referred for a clinically indicated echocardiogram; the echo must be of good quality and specifically have patient height, weight, left ventricular outflow tract diameter, subaortic velocity profile by Doppler, and aortic transvalvular continuous wave Doppler velocity profile. For mitral regurgitation and aortic regurgitation the data must be adequate to allow calculation of regurgitant volume. For hypertrophic cardiomyopathy, a recording of left ventricular outflow tract peak velocity must be recorded