1. Department of Cardiology, Clinical Sciences, Lund University, SE-221 85, Lund, Sweden
2. Department of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, 50, Pervomayskaya st., 167982, Syktyvkar, Russia
3. Department of Physiology, Medical Institute of Syktyvkar State University, 11, Babushkin st., 167000, Syktyvkar, Russia
4. Federal Medical Research Center, 2, Akkuratov st., 197341, St. Petersburg, Russia
5. Arrhythmia Clinic, Skåne University Hospital, SE-22185, Lund, Sweden