Role of the old and new echocardiographic technologies in cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an important tool for the therapy in patients withchronic heart failure, as it is able to correct the heterogeneity of regional left ventricular mechanical contraction, known as dyssynchrony. Although this therapy is strongly indicated in patients with both heart failure with left ventricular systolic dysfunction and wide QRS at electrocardiogram, about one-third of these patients are non-responders. Since the degree of mechanical dyssynchrony can be widely variable, it is interesting to quantify dyssynchrony by imaging methods, such as echocardiography, which might be able to lead to a mile selection of patients who are candidates for CRT. This article will review the role of old and new echocardiographic methods in predicting response to CRT.