RESUMO
Assessment of the left ventricular ejection fraction plays a key role in the echocardiographic diagnosis of heart failure. The parameter most commonly used is the ejection fraction computed with the biplane disc summation method of Simpson; however, there are numerous limitations to this method, such as the assumption of geometrical symmetry, a substantial intraobserver and interobserver variability, foreshortening of the left ventricle and insufficient image quality for endocardial tracking. Alternative parameters for the evaluation of left ventricular function should be taken into consideration. Speckle tracking echocardiography has proven to be a reliable prognostic factor and a good tool for differentiating cardiomyopathies. Simple measurements, which are also feasible with poor image quality, are mitral annular plane systolic excursion (MAPSE) and the velocity of mitral annular movement (Sm or S'). In mitral regurgitation, left ventricular dP/dt represents the time to build up a certain pressure gradient and is therefore a measure of the contractile force exerted. Three-dimensional echocardiography has proven to be an important tool not only for three-dimensional measurement of the left ventricular ejection fraction but also for multivectoral speckle tracking analysis.
