This chapter Velocity Vector Imaging represents an important tool in the ongoing effort to better measure the 3D nature of cardiac motion, detect pathology, and assess response to treatment. Like other speckle-tracking algorithms, and all forms of cardiac imaging in general, it has both the strength of apparent simplicity and the weakness of analyzing only a piece of the more complex myocardial architecture are described in detail. It has the capability of generating a tremendous amount of data from each image, but how this data can best be used for clinical decision-making remains to be determined. For strain in particular, consensus is needed on whether LaGrangian or Eulerian strain is the most robust measurement. Velocity vector imaging also has the capability to be applied to nonspeckle-based images, such as CMR datasets. As the use of VVI and other forms of torsional analysis increases, it is important to sound a cautionary note: electrical–mechanical coupling in the human heart operates on a millisecond to millisecond basis, with a mere 60 milliseconds separating a normal QRS duration from profound bundle branch block. For standard imaging storage rates of 30 Hz, this represents less than two full frames of imaging data (33 ms/frame). Crucial segments of the cardiac cycle, such as isovolumetric contraction and relaxation, take place in even shorter time periods, which currently require the extremely fine temporal resolution of spectral Doppler or M-mode for detection. 18 comprehensive and self-explanatory images are included in this chapter. And 223 references are given at the end of the chapter to facilitate further reading.