Heart failure (HF) is the most important cause of death in the world. The prognosis is very poor and strictly dependent on the therapy that should be continuously optimized in function of the mechanical behaviour of the ventricle. To follow the evolution of the disease, we are testing an approach based on the biomechanical coupling between failed heart and aorta, which considers end systolic ventricular volume referred to pressure, stroke volume referred to aortic pulse and a new non invasive index of left ventricular contractility validated by Zhong et al. To test the sensitivity of our approach to monitor the HF condition and evolution, a follow up program of 10 HF patients submitted to cardiac resynchronization therapy is on course and will be concluded in the next three months