Acute Assessment of a Micro Multipolar Lead for Enhanced Cardiac Resynchronisation Therapy

Inclusion Criteria: * Male or female patient aged ≥18 years old. * Patient presenting a CRT-P or CRT-D indication according to the latest ESC guidelines . * Primary implant of a CRT device (including upgrade from a single or dual-chamber pacemaker or ICD). * Signed and dated informed consent. * Patient affiliated with, or beneficiary of a social security category. Exclusion Criteria: * Class IV of NYHA (ambulatory or not). * Allergy to contrast media used for imaging during cardiac catheterization. * Severe Renal Failure (clearance of creatinine \< 30ml/mn/m²). * Previous failure catheterization of the coronary sinus, or previous failure of left ventricular lead implantation. * Already included in another clinical study involving intra-cardiac active implantable device, or participation to any other clinical trial in the last 2 weeks. * Person deprived of liberty by administrative or judicial decision or placed under judicial protection (guardianship or supervision). * Known pregnancy, breastfeeding women or in childbearing age without an adequate contraceptive method (failure rate \< 1%).