Function and mechanics of the left ventricle: from tissue Doppler imaging to three dimensional speckle tracking.

One of the most common indications in echocardiography is the evaluation of left ventricular function. The traditional measurement of ejection fraction is based upon tracing the left ventricular borders and calculating left ventricular volumes using geometric assumptions. Now, with the introduction of three-dimensional echocardiography, the evaluation of left ventricular function is easier to carry out and with superior accuracy and reproducibility. However, regional myocardial function is more difficult to evaluate because it relies on visual assessment of endocardial motion and wall thickening. Currently, new techniques like tissue Doppler and speckle tracking imaging allow regional and global quantification of myocardial function through new parameters, like deformation/strain, rotation and twist. In this regard, speckletracking echocardiography (STE) has been introduced as a technique for angle-independent quantification of multidirectional myocardial strain and rotation. With the arrival of three-dimensional systems, the entire left ventricle can be evaluated with this technique, lacking the inherent weakness of two- dimensional and tissue Doppler methods. Three dimensional speckle tracking (3DST) has potential to be an ideal tool to assess not only global myocardial function but regional function through deformation, rotation, twist and untwisting parameters.