Dyssynchrony Indices To Predict Response to Cardiac Resynchronization Therapy

131 patients with heart failure, wide QRS, and left ventricular ejection fraction <35% undergoing cardiac resynchronization therapy (CRT)

Echocardiographic dyssynchrony indices (14 indices by M-mode, tissue velocity, tissue Doppler strain, 2D speckle strain, 3D echocardiography, and timing intervals)

Reverse remodeling (end-systolic volume reduction ≥15%) and clinical response (assessed by Minnesota Living with Heart Failure Questionnaire, 6-minute walk distance, and peak oxygen consumption) at 6 monthssurrogate