Video 6.8
Video 6.8: Tricuspid regurgitation in a child with pulmonary atresia and intact ventricular septum. Note the proximal isovelocity surface acceleration as the regurgitant jet approaches the regurgitant orifice. Lines of increasing velocity are seen as aliasing of the color flow (dark blue to light blue). The surface area of the PISA hemisphere times the Nyquist limit (73.2 cm/s in this example) can be used to approximate the regurgitant volume.