Many studies have shown the benefits of cardiac resynchronization therapy (CRT) with biventricular pacing in patients with heart failure with left ventricular dysfunction. CRT restores contraction coordination between different regions of the left ventricle, which yields a significant improvement in LV systolic function, symptoms, exercise tolerance and quality of life. In the longer term, treatment with resynchronization induces a reverse remodeling of the left ventricle and a decrease in mortality and morbidity (hospitalization for heart failure). Nevertheless, even if a majority of patients treated with CRT feel the benefit, some (up to 40% depending on the response criteria of CRT) do not experience significant improvement (nonresponders). Echocardiography and imaging have not so far demonstrated their added value to optimize delivery of CRT. Monocentric promising work on limited numbers of patients, however, were carried out. Meanwhile, equipment for delivering CRT evolves and new probes with four poles stimulation of the left ventricle are now used. The objective of this research is to validate new sequences of ultrasound processing estimating the CRT. These tools are based on usual echocardiographic examination of patients

Pilot study for testing tools pre and post-treatment images echocardiography but also MRI with a descriptive purpose and identification of the computed parameters should be secondarily test a large multicenter cohort . Patients in the study will be explored in RICART preimplantation as then in the manner used in current clinical routine. The use of data by cons will focus on the study of new tools ever compared in the same patients.

Data echocardiography (as with other techniques) are those used in clinical routine. Then, the data processing to be carried characterized the asynchrony posteriori, regardless of initial clinical data on a dedicated search software. Each quantitative parameter will be compared with others in order to predict the response to resynchronization. Response prediction of threshold values to the resynchronization can be obtained and compared to each of the tools. The value of relative and an addition to another may be tested.

The predictive value of the change (delta) of each parameter between the pre- and post-implantation to predict response to al resynchronization, will be evaluated.

Inclusion Criteria:

• Any patient with sinus rhythm sent to hospital for a cardiac resynchronization according to ESC criteria and implanted with a left ventricular pacing lead quadrupole

Exclusion Criteria:

• Patients with an acoustic window is incompatible with the accurate echographic assessment of heart function
• Patients with spontaneous one year prognosis is not dependent on his heart or another disease to the forefront (eg neoplasia)
• Contra-indications to MRI (pacemaker or implantable defibrillator, intracranial ferromagnetic surgical clips, cochlear implants, intraocular metallic foreign body, Starr-Edwards heart valve prosthesis pre 6000, biomedical device type pump insulin or neurostimulator) or against -indications to iodinated contrast injection (severe renal impairment, allergy).
• Patient not giving free and informed consent.