Fig. 3

High frame rate color TDI shear wave tracking and analysis in the postprocessing software. a: classical parasternal long axis view and the focused TDI window over the interventricular septum. b: An M-Mode line is put in the septal wall, pointing towards the shear wave source. c: virtual M-mode map of a full heart cycle (reconstructed offline), at 510 Hz frame rate, demonstrating the shear waves after mitral and aortic valve closure (dotted slopes). The onset of the waves is marked with solid lines. The shear wave after aortic valve closure is pointed to by the dotted arrow; space and time directions are also indicated. d: mean tissue velocity curve as a function of time (averaged over the M-mode line, this velocity should not be mistaken with the shear wave propagation velocity), synchronous to the ECG (green) and PCG (yellow). The onset of both shear waves is synchronous to the onset of the respective heart sounds (S1, S2)