This prospective, randomized study will investigate, if information of the catheter force during ablation of a left anterior line does reduce total RF application time by prevention of ineffective lesions.

Catheter ablation has emerged as a realistic therapeutic option for symptomatic atrial fibrillation (AF).

The three main techniques described for ablation of persistent AF include pulmonary vein (PV) isolation, ablation based on electrogram analysis, and left atrial (LA) linear lesions.

The ideal endpoint of linear lesions should be complete electrical block; however, this is technically challenging, time consuming, and potentially hazardous. The ST catheter combined with 3D mapping and navigation software, gives physicians a real-time, objective measure of tip-to-tissue contact force during the catheter ablation procedure and will allow physicians to more safely and effectively treat atrial fibrillation.

Inclusion Criteria:

• Patients with symptomatic atrial fibrillation and additional substrate modification or perimitral flutter
• Patients with persistent atrial fibrillation
• Patients with perimitral flutter
• Patients with recurrence after a circumferential PV isolation procedure
• Patients with paroxysmal atrial fibrillation and AF episodes lasting > 7 days
• Patients (>18 und <80 Jahre)

Exclusion Criteria:

• moderate to severe valvular heart disease,
• congenital heart disease
• reduced left ventricular function (ejection fraction <35%)
• any reversible cause for atrial fibrillation (e.g. hyperthyroidism)
• intracardiac thrombi documented by transesophageal echocardiography
• myocardial infarction within 3 months, cardiac surgery in the previous three months