[1] AHEPA Univ Hosp, Dept Cardiol, Thessaloniki, Greece
[2] Gen Hosp George Papanikolaou, Dept Cardiol, Thessaloniki, Greece
[3] Attikon Univ Hosp, Cardiol Dept 2, Athens, Greece
[4] Tzaneio Gen Hosp Piraeus, Dept Cardiol, Athens, Greece
[5] Mitera Childrens Hosp, Dept Congenital Heart Dis, Athens, Greece
[6] Ippokrate Univ Hosp, Dept Cardiol, Athens, Greece
[7] Mediterraneo Hosp, Dept Cardiol, Athens, Greece
[8] Onassis Cardiac Surg Ctr, Dept Pediat Cardiol, Athens, Greece
[9] Interbalkan Hosp, Dept Cardiol, Thessaloniki, Greece
[10] Gen Hosp Kavala, Dept Cardiol, Kavala, Greece
[11] St Lukes Clin, Dept Cardiothorac Surg, Thessaloniki, Greece
[12] Univ Hosp Larissa, Dept Cardiol, Larisa, Greece
[13] Univ Hosp Ioannina, Dept Cardiol, Ioannina, Greece
[14] Gen Childrens Hosp Pan & Aglaia Kyriakou, Dept Pediat Cardiol, Athens, Greece
[15] Achillopouleio Gen Hosp, Dept Cardiol, Volos, Greece
[16] Univ Hosp Patras, Dept Cardiol, Patras, Greece