1. Department of Cardiology, Oslo University Hospital, Rikshospitalet , Sognsvannsveien 20, 0372 Oslo , Norway
2. Department of Electrophysiology, Republican Specialized Scientific Practical Medical Center of Cardiology , Osiyo St. 4, 100052 Tashkent , Uzbekistan
3. Institute of Clinical Medicine, University of Oslo , Sognsvannsveien 20, 0372 Oslo , Norway