all patients treated with rivaroxaban chronically, (atrial fibrillation non-valvular under current amm) for less than one year whatever anti vitamin k treatment history

affiliate or beneficiary of a social security system.

patient who formulated its "does not oppose" to participate in this research

age higher than or equal to 18 years

opposition to participation

patient don't understand french language

patient does not have responsibility for the management of treatment (treatment administered by a nurse at home, or by caregivers)

tutorship or curatoship

law-protected patient

pregnant women or breast-feeding