| Clinical characteristics of the study population | 
      
        |  | PAF Group (29) | Chronic AF
          Group (9) | Control Group (21) | 
      
        | Age | 67 (± 9.8) | 69 (± 9.6) | 62 (± 15.3) | 
      
        | Gender male/female | 18/11 | 6/3 | 10/11 | 
      
        | Sinus bradycardia | 1 (3%) |  |  | 
      
        | Hypertensive crisis | 2 (7%) |  |  | 
      
        | Coronary 1 vessel
disease | 3 (10%) |  | 3 (14%) | 
      
        | Coronary 2 vessel
disease | 1 (3%) |  | 1 (5%) | 
      
        | Coronary 3 vessel
disease | 3 (10%) |  |  | 
      
        | Ischemic
cardiomyophathy |  | 1 (11%) |  | 
      
        | Unselected chronic
heart disease | 1 (3%) |  | 2 (10%) | 
      
        | Diabetes mellitus | 1 (3%) |  |  | 
      
        | Sinus tachycardia |  | 1 (11%) |  | 
      
        | Orthostatic disorder |  | 1 (11%) |  | 
      
        | Medication |  |  |  | 
      
        | Beta-blocking-agents | 22 (76%) | 4 (44%) | 12(57%) | 
      
        | Calcium-channelblockers | 1 (3%) | 1 (11%) |  | 
      
        | ACE inhibitor | 3 (10%) |  |  | 
      
        | AT1 inhibitor | 3 (10%) |  |  | 
      
        | Digitalis | 2 (7%) | 1 (11%) |  | 
      
        | No medication |  |  | 3 (14%) |