Predictors of response to cardiac resynchronization therapy--importance of left ventricular dyssynchrony.

Background: Cardiac resynchronization therapy (CRT) is currently used in selected patients with dilated cardiomyopathy and heart failure. However, 30% of patients do not respond to CRT when selection is based on clinical and electrocardiographic criteria. Left ventricular dyssynchrony can be evaluated by tissue Doppler imaging and it has been described as a useful precdictor of response to CRT.