The objective of this work is to identify the determinants and consequences of myocardial fibrosis in HCM, particularly the relationship between fibrosis and left ventricular dysfunction assessed by the analysis of myocardial deformation and between fibrosis and heart failure. The study of fibrosis, which concerns 30 to 70% of patients and replace 1 to 70% of the myocardial tissue, is made possible in vivo by analysis of delayed enhancement gadolinium in MRI. This work aims to study the relationship between myocardial fibrosis, heart function assessed by myocardial deformation, heart failure, and biological profile (proteomics) of patients at rest and after exertion.