Inclusion Criteria:  Paroxysmal AF ≥ once per month that causes moderate to severe symptoms and leads to significant distress or interferes with daily life (i.e. EHRA class ≥ IIb); Scoring ≥ 20 on the Cardiac Anxiety Questionnaire at screening; Age 18-75 years; On optimal medical treatment; Able to read and write in Swedish.  Exclusion Criteria:  Heart failure with severe systolic dysfunction (ejection fraction ≤ 35%); Significant valvular disease; Planned ablation for AF or ablation within 3 months before assessment; Other severe medical illness; Any medical restriction to physical exercise; Severe psychiatric disorder, severe depression, or risk of suicide; Alcohol dependency; Previous participation in any AF-CBT study conducted by the research group.