Echocardiographic evaluation of cardiac dyssynchrony.

First described a decade ago, cardiac resynchronization therapy (CRT) has recently become a proven therapeutic strategy for refractory heart failure. Large clinical trials have shown a reduction in both morbidity and mortality in patients treated with CRT. Initial patient selection has relied mainly on electrocardiographic criteria, which allows identification of only 70% of responders. Accordingly, echocardiographic criteria were developed to identify mechanical dyssynchrony in an effort to improve patient selection. Multiple echocardiographic criteria have since been proposed, with no consensus as to which parameter better predicts CRT response. Although comparison studies using different criteria are underway, current evaluation of dyssynchrony should probably use an integrated multiparameter approach. The objective of the present article was to review the role of echocardiography in the evaluation of cardiac dyssynchrony in clinical practice.