[1] Univ Autonoma Barcelona, Hosp Univ Vall dHebron, Serv Cardiol Pediat, Barcelona, Spain
[2] Univ Girona, Hosp Univ Dr Josep Trueta, Serv Cardiol Pediat, Girona, Spain
[3] Hosp Univ Vall dHebron, Serv Cardiol, Unidad Arritmias, Barcelona, Spain
[4] Royal Brompton Hosp, Paediat Cardiol Dept, London, England