Atrial Fibrillation/Sinus Rhythm Before and After Cardioversion

Inclusion Criteria: * patients with atrial fibrillation and planned cardioversion * male and female patients aged at least 18 years * patients being able to understand and to follow the study staff´s instructions * signed informed consent Exclusion Criteria: * persons being hosted in an institution by administrative order or court injunction * pregnancy or breast feeding * persons not being able to consent * persons with implanted electronic devices * material incompatiblity * acute or chronic inflammation of the external or middle ear canal * abnormal anatomic ear canal (congenital or pathological) * persons in a dependent relationship to the investigator or employment contract