Inclusion Criteria:  Symptomatic paroxysmal or persistent AF that was resistant to medical acceptable daily dose therapy in patients who were free of exclusion criteria and accepted to sign the written fully informed consent to undergo CA and to give pre-procedural blood samples.  Exclusion Criteria:  History of the presence of longstanding persistent or permanent AF, myocardial infarction, acute coronary syndrome (ACS), significant heart failure (NYHA3), dilated or hypertrophic cardiomyopathy, left ventricular ejection fraction (LVEF)< 35%, congenital pathologies, significant valvular heart disease, pulmonary embolism, venous thrombosis, intracardiac thrombus or inability to take warfarin or other oral anticoagulants, hepatic or renal insufficiency, acute inflammatory states (sepsis, chronic obstructive pulmonary disease in acute phase), cancer, autoimmune pathologies.