Assessment of left ventricular dyssynchrony for the prediction of response to CRT: The role of conventional echocardiography and 3D echocardiography E Liodakis, Gabe B Bleeker, Jeroen J Bax, and Petros Nihoyannopoulos

At present, cardiac resynchronization therapy (CRT) is considered a major breakthrough in the treatment of selected patients with drug-refractory heart failure.1,2 In large randomized trials, CRT was able to improve heart failure symptoms and left ventricular (LV) function. In addition, CRT resulted in a significant reduction in the number of heart failure-related hospitalizations and an improvement in patient survival.1,2 However, closer analysis of the results of these trials revealed that 20-30% of patients did not improve in clinical symptoms when patients were selected according to the established CRT selection (New York Heart Association (NYHA) class III and IV, LV ejection fraction (LVEF) <35%, and QRS complex width >120 ms).3,4 This observation highlights the need for refinement of the current selection criteria in order to reduce the number of patients without response to CRT.