[Role of echocardiography on the diagnosis is ventricular dyssynchrony in patients selected for cardiac resynchronization].

Currently, cardiac resynchronization therapy (CRT) is a treatment for heart failure refractory to optimized medical therapy. However, approximately 30% -45% of patients selected according to the guidelines, are "non responders" to CRT. Since the CRT is an invasive treatment, the candidates for such therapy should be carefully selected to ensure an optimal clinical benefit and instrumental. Despite its demonstrated effectiveness in reducing mortality and hospitalizations in patients with chronic heart failure on optimal medical therapy, the diagnosis of dyssynchrony is not easy. On the one hand, some echocardiographic indices have proved unreliable, other, more complex parameters still need to be validated before being implemented in clinical routine. The purpose of our paper is to evaluate echocardiographic techniques and not consolidated in patient response to CRT.