The role of echocardiography in the assessment of mechanical dyssynchrony and its importance in predicting response to prognosis after cardiac resynchronization therapy.

The aim of this review is to synthesize the published evidence regarding the benefits of identifying mechanical asynchrony before implantation of biventricular devices, and the role of echocardiography in the identification and quantification of mechanical asynchrony. It summarizes the published studies addressing the several echocardiographic parameters of dyssynchrony that have already proven to predict response to cardiac resynchronization therapy. M-mode echocardiography, Doppler tissue imaging, strain and strain rate imaging, tissue tracking, and 3-dimensional echocardiography parameters of dyssynchrony shown to be able to identify responders are discussed. In addition, the prognostic implication of the identification of mechanical asynchrony before implantation is addressed. A summary of the published evidence of the echocardiographic parameters able to identify patients more likely to derive a prognostic benefit is provided. Finally, it mentions some of the current uncertainties and possible future applications of echocardiographic evaluation of dyssynchrony.