Three-dimensional echocardiographic evaluation of mechanical dyssynchrony in systolic heart failure with narrow QRS complex

3DE confirmed significant dyssynchrony in  > 50% HF patients with narrow QRS as demonstrated by other imaging methods. 3D distribution patterns of asynchronous segments indicate possibility of left ventricular mechanics related reasons responsible for lack of CRT responsiveness, an observation that generates hypothesis on possible reasons of CRT non-responsiveness.