Pulse doppler waveform measuring peak aortic velocity and velocity time integral (VTi). The upper half of the image displays an apical 5 chamber view with pulse doppler gate at the aortic outflow tract. The lower half of the image displays doppler waveform (m/sec). The waveform is traced to estimate VTi and measure peak aortic velocity. RV, right ventricle; LV, left ventricle; RA, right atrium; LA, left atrium; VTi, velocity time integral.