The Trial will evaluate the influence of oesophageal probes in Radio frequency (RF)-ablation of atrial fibrillation regarding oesophageal ulcers after ablation.

The Trial will evaluate the influence of oesophageal probes in RF-ablation of atrial fibrillation regarding oesophageal complications after ablation.

200 patients will be prospectively randomised into 2 groups. The conventional group will undergo RF-Ablation of atrial fibrillation using an oesophageal probe to measure the temperature during ablation.

In the other group will receive ablation using fixed energy levels (25 Watt) at the posterior left atrial (LA) Wall without an oesophageal probe , All patients will get a gastroscopy for evaluation of oesophageal complications the day after the procedure.

All patients will have a 6 months follow up (FU) in our clinic to be reevaluated for complications (primary endpoint) and rhythm stability. (secondary endpoint)

Inclusion Criteria:

• 12 lead ECG with documented atrial fibrillation
• Indication for RF ablation of atrial fibrillation according to the recent guidelines
• Signed informed consent
• Age 18-85 years

Exclusion Criteria:

• Pregnancy or possible pregnancy without negative test within 48h prior to ablation
• Intracardiac thrombus
• Contraindication for oral anticoagulation
• Conditions, that may complicate the positioning of the oesophageal probe