The purpose of this study is to compare two strategies of catheter-based treatment of paroxysmal atrial fibrillation: Pulmonary vein isolation either alone or combined with electrogram-guided substrate-ablation.

Catheter ablation has evolved an accepted alternative in the curative treatment of atrial fibrillation (AF). However, discussion about the best ablation strategy is still ongoing.

In patients with paroxysmal AF, it has been reproducibly demonstrated that curing rates of approximately 65-70% can be achieved with the electric isolation of pulmonary veins (PV) eliminating the initiating triggers of AF episodes. Recently, a new catheter ablation approach targeting in both atria fractionated, complex electrograms during ongoing AF and modifying thus the substrate maintaining AF has been described. The first describer of this technique reports curing rates of 92%. We want to compare in a randomized prospective study the treatment by PV isolation alone with a combined approach of PV isolation together with ablation of fractionated complex electrograms in patients with paroxysmal AF. Study endpoint is the achievement of stable sinus rhythm as assessed by 7 days holter ECG in the absence of antiarrhythmic drug treatment.

Inclusion Criteria:

• Age > 18 and <80 years
• Symptomatic paroxysmal atrial fibrillation
• Drug-refractory
• Anticoagulation

Exclusion Criteria:

• Hyperthyreosis
• Moderate-to-severe mitral valve valvulopathy
• LV-ejection fraction <35%
• Prior ablation, PCI or heart surgery <3 months
• Left atrial thrombus