Dyssynchrony estimation using echocardiography is increasingly used as a quantitative tool to qualify candidates for cardiac resynchronization therapy (CRT) and evaluate its effect post procedure. Conventionally, tissue Doppler imaging (TDI) has been used for this application, but its utility and accuracy are limited by the angle of incidence-dependent nature of Doppler velocity measurement. Recently, speckle tracking technology applied to B-mode images has been developed for wall motion analysis including dyssynchrony estimation. Regional motion is tracked by observing the movement of two-dimensional (2D) speckle patterns in ultrasound images. Three-dimensional (3D) speckle tracking is also possible and can be used to evaluate 3D cardiac motion of the entire left ventricle. Speckle tracking can provide assessment of regional strain and dyssynchrony in cardiac motion for more objective diagnosis.