[1] Univ Belgrade, Sch Med, Belgrade, Serbia
[2] Clin Ctr Serbia, Cardiol Clin, Belgrade, Serbia
[3] Med Univ Carol Davila, Colentina Univ Hosp, Bucharest, Romania
[4] Natl Heart Hosp, Sofia, Bulgaria
[5] Univ Hosp Ctr Mother Theresa, Clin Cardiol, Tirana, Albania
[6] Clin Internal Dis, Dept Cardiol, Tuzla, Bosnia & Herceg
[7] Clin Hosp Ctr Sestre Milosrdnice, Zagreb, Croatia
[8] Univ Clin Ctr Podgorica, Podgorica, Montenegro
[9] Cty Emergency Hosp, Ctr Cardiol, Craiova, Romania
[10] Med Univ Carol Davila, Dept Internal Med, Emergency Clin Hosp, Bucharest, Romania
[11] Clin Ctr Vojvodina, Novi Sad, Serbia
[12] Multiprofile Hosp Act Treatment, Burgas, Bulgaria
[13] Clin Hosp Ctr Rijeka, Rijeka, Croatia
[14] Univ Birmingham, City Hosp, Ctr Cardiovasc Sci, Birmingham B18 7QH, W Midlands, England