Inclusion Criteria:  Patients of both gender, over 18 years old, with transthyretin amyloid cardiopathy according to one of the two American Heart Association definitions of 2016 No mutation in the TTR gene Patients giving their free and informed consent to participate after information about the research Patients affiliated to or benefiting from a social security scheme  Exclusion Criteria:  Patients with chronic neuropathy related to a known aetiology Patients under guardianship or curatorship