<qa>  How many patients will undergo a two-stage, hybrid ablation?60 patients will undergo a two-stage, hybrid ablation, all of them will have an ECG monitoring device implanted and will be followed for up to three years. Neurological safety of both surgical and catheter procedures will be assessed by three examinations. Magnetic resonance will be performed before surgery, 5 days after surgery and at the 180 days visit to search for subclinical cerebral ischemia. Complex neuropsychological examination will be performed before surgery, afer 1 month after surgery and at 180 days visit to search for changes in cognitive functions, behavioral functions etc. Transcranial Doppler will be performed during surgical and catheter ablation to detect microembolic signals. 