PURPOSE Physical exercise is beneficial for patients with ischemic heart disease and chronic heart failure, while little is known about the effect in atrial fibrillation (AF). The investigators studied the effect of physical exercise on cardiac output (CO), max. exercise capacity, biomarkers and quality of life (Qol) in patients with AF in a randomised study of physical exercise training three times weekly for twelve weeks.

HYPOTHESIS Exercise training improves cardiac output (CO), max. exercise capacity, biomarkers and quality of life (Qol) in patients with AF.

METHODS Assessment of exercise capacity, CO, Qol, body composition, six minute walk test and muscular strength was performed before and after 12 weeks.

Resting echocardiography was done at baseline. CO was measured using impedance cardiography at rest and during maximal exercise testing on an ergometer bicycle. Body composition, muscular strength and six minutes walking capacity were measured before and after the training period. Qol was evaluated by the use of the standardized validated questionnaires Short Form 36 (SF-36) and the Minnesota Living with Heart Failure Questionnaire (MLHF-Q).

Training consisted of aerobic exercise at 70 percent of max. capacity estimated by Borg-scale.

Inclusion Criteria:

• Adult subjects in permanent atrial fibrillation, willing to participate in a 12 weeks training program and able to give informed consent to participation were eligible for the study.

Exclusion Criteria:

• Subjects with severe refractory hypertension
• previous heart valve surgery, moderate to severe COPD
• restrictive lung disease, moderate to severe asthma
• pregnant or lactating subjects
• patients with a very low life expectancy
• patients who were unable to exercise or comply with the study protocol