Heart failure is a major public health problem, with limited treatment options. Many patients with heart failure develop mechanical dyssynchrony, with associated further deterioration in heart function. Some patients with heart failure and dyssynchrony benefit from cardiac resynchronization therapy (CRT), but a third or more of heart failure patients selected for treatment with CRT with conventional criteria fail to benefit significantly from it. The primary goals of this project are: 1) development and evaluation of magnetic resonance imaging (MRI) and image analysis methods to better predict outcome of the use of cardiac resynchronization therapy (CRT) for heart failure with dyssynchrony, and 2) use of the imaging-derived data for computer modeling of the effects of the dyssynchrony on cardiac function and its response to CRT. As heart failure is an important clinical condition, and as current means used to predict response to CRT have limited accuracy, this project is potentially clinically very significant.