Objective: Whilst a large volume of research has been conducted showing the relevance of measures of psychological distress as risk factors and consequences of cardiovascular disease, only few have investigated this with regard to Atrial Fibrillation (AF). Health Related Quality of Life (HRQoL) has been shown to be seriously impaired in AF patients in many studies, however, a deeper understanding of the mental health issues is lacking. Methods: Using clinical data from two trials conducted by the competence network for atrial fibrillation in Germany (n=770 at baseline), we have conducted cross-sectional and longitudinal analyses of mental health parameters and HRQoL in AF patients. An in-depth battery of questionnaires on mental health parameters (including vital exhaustion, symptom burden, illness intrusiveness, patient perceptions of disease severity and depression) were included. Results: The prevalence of major depression in AF patients (8%) is more than double that of general population estimates. The healthiest subgroup of patients has a two-fold increased risk of suffering from vital exhaustion. Both depression and vital exhaustion are significantly more prevalent in persistent that paroxysmal patients, contrary to expectations. In addition, depression is associated with worsened patient-physician communication, and with the reporting of more severe AF related symptom burden, after adjustment for clinical measures of disease severity. AF patients without comorbidities and with minimal symptom burden have impaired quality of life in comparison to the general population. Conclusions: Quality of life and psychological comorbidity are alarmingly elevated even in the healthiest of AF patients in the clinic.