Recently a combined approach of surgeon ablation in combination with endocardial ablation (hybrid ablation) has been introduced. This therapy has shown excellent results in patients with previous failed endocardial ablation for paroxysmal atrial fibrillation as well in patients with persistent atrial fibrillation. The investigators hypothesize that the severity of atrial remodeling in patients with atrial fibrillation can be measured by clinical factors, echocardiographic parameters, circulating biomarkers and genetic background, and that these factors can be used to identify a risk profile to predict failure of the hybrid ablation therapy in patients with atrial fibrillation. Aim of this study is to determine a risk profile based on clinical correlates, circulating biomarkers, and genetic background associated with failure of the hybrid ablation procedure, in a prospective single center registry setting. The investigators evaluate all consecutive patients who have agreed to undergo the hybrid ablation procedure because of atrial fibrillation. The investigators aim for a total of 250 participants. Extra study related procedures include blood sampling for biomarkers and genetic analysis, prolonged Holter monitoring for documentation of recurrences of atrial fibrillation/atrial flutter/atrial tachycardias, and a quality of life questionnaire. Total follow-up will be five years.

Main study endpoint is failure of the hybrid ablation procedure in patients with atrial fibrillation, i.e. any (a)symptomatic atrial fibrillation/atrial flutter/atrial tachycardia >30sec without anti-arrhythmic drugs at one year of follow-up by ECG recording and 3-day Holter monitoring.

Rationale: The investigators hypothesize that the severity of atrial remodeling in patients with atrial fibrillation can be measured by clinical factors, echocardiographic parameters, circulating biomarkers and genetic background, and that these factors can be used to identify a risk profile to predict failure of the hybrid ablation therapy in patients with atrial fibrillation.

Objective: To determine a risk profile based on clinical correlates, circulating biomarkers, and genetic background associated with failure of the hybrid ablation procedure in patients with atrial fibrillation.

Study design: A prospective single center registry. Study population: Patients who have agreed to undergo the hybrid ablation procedure because of atrial fibrillation. The investigators aim for a total of 250 participants.

Intervention: Extra study related procedures include blood sampling for biomarkers and genetic analysis at baseline and 1 year follow-up; prolonged Holter monitoring for documentation of recurrences of atrial fibrillation/ atrial flutter/atrial tachycardias at 3 months, 6 months and 1 year follow-up; and a quality of life questionnaire at baseline, and at 1 year and 5 year follow-up.

Total follow-up duration: Five years. Main study endpoints: Failure of the hybrid ablation procedure in patients with atrial fibrillation, i.e. any (a)symptomatic atrial fibrillation/atrial flutter/atrial tachycardia >30sec without anti-arrhythmic drugs at one year of follow-up by ECG recording and 3-day Holter monitoring.

Inclusion Criteria:

• Patients who have agreed to undergo the hybrid ablation procedure because of atrial fibrillation.

Exclusion Criteria:

• None.

Patients who have agreed to undergo the hybrid ablation procedure because of atrial fibrillation.