The Biorhythm study aims to investigate the utility of new biomarkers (e.g. MR proANP, ST2) measured pre-procedure for the prediction of procedural success in patients with atrial fibrillation undergoing cardioversion or ablation.

This is a prospective, observational, multicentre study of patients with paroxystic or persistent atrial fibrillation scheduled to undergo cardioversion or ablation of AF in routine practice. Serum levels of MR proANP and ST2 pre-procedure will be measured to attempt to identify a threshold that carries prognostic value for procedural success (maintenance of sinus rhythm at one year).

Inclusion Criteria:

• Patients with paroxystic or persistent atrial fibrillation for whom a decision to perform ablation is made.
• Patients with persistent atrial fibrillation for whom a decision to perform cardioversion is made.
• Patients with social security coverage, or beneficiary thereof.
• Patients who provide written informed consent.

Exclusion Criteria:

• Age <18 years or >80 years
• Patients with significant valvular heart disease defined as symptomatic aortic valve disease, severe aortic or mitral stenosis or tricuspid or mitral insufficiency grade 3/4 or 4/4
• Patients with pulmonary arterial hypertension >45 mmHg on echocardiography
• Patients with chronic respiratory disease, chronic obstructive pulmonary disease stage II, III or IV.
• Patients with a left ventricular ejection fraction <45%
• Patients with recent (<1 month) acute decompensation of heart failure
• Patients with recent (<1 month) acute coronary syndrome
• Anemia (hemoglobin <10 g/dL)
• Pregnant or lactating women
• Patients with anticipated poor compliance, as assessed by the study investigator
• Patients within the exclusion period of another clinical study
• Patients under legal guardianship