Single center prospective study to analyze the impact of diabetes mellitus on patients' outcome following radiofrequency-guided catheter ablation for atrial fibrillation.

A total number of 50 patients with diabetes mellitus will undergo radiofrequency-guided catheter ablation for atrial fibrillation. Pre-procedural cardiac MRI will be performed with late-gadolinium enhancement to visualize the individual amount and distribution of fibrosis in the right and left atrium. The relationship between diabetes mellitus and individual atrial arrhythmia substrates as well as patients' outcome following catheter ablation will be analyzed.

Inclusion Criteria:

• Patients undergoing their 1st radiofrequency-guided catheter ablation for atrial fibrillation
• Diabetes mellitus
• Able to understand and willing to sign the Informed Consent Form.
• Age ≥18 years.

Exclusion Criteria:

• Contraindication for DE-MRI with a full dose of gadolinium-based contrast agent.
• Previous left atrial ablation or surgical procedure
• Women currently pregnant, breastfeeding, or of childbearing age not currently taking or not willing to use a reliable form of contraception
• Mental or physical inability to take part in the study
• Morbid obesity (BMI > 35), or inability to be placed in MRI due to body mass.

A total of 50 consecutive patients with diabetes mellitus and symptomatic atrial fibrillation will be included in this prospective observational analysis. All patients will be treated for atrial fibrillation at the Heart and Diabetes Center NRW, Bad Oeynhausen, Germany. Written informed will be obtained from each patient, the study concept complies with the Declaration of Helsinki and the institutional review board already approved the study design. Catheter ablation will be performed under deep sedation. In all patients preprocedural magnetic resonance imaging (MRI) will be performed prior to the intervention to visualize the individual amount and distribution of fibrosis and to visualize the anatomical location and course of the esophagus.