[1] Johns Hopkins Univ Hosp, Taussig Heart Ctr, Dept Pediat, Baltimore, MD 21287 USA
[2] Univ Nebraska Med Ctr, Childrens Hosp & Med Ctr, Omaha, NE USA
[3] Univ Bologna, Dept Elect Elect & Informat Engn, Bologna, Italy
[4] Univ Alberta, Stollery Childrens Hosp, Dept Pediat, Div Cardiol, Edmonton, AB, Canada
[5] Univ Milano Bicocca, Dept Med & Surg, Milan, Italy
[6] IRCCS, Ist Auxol Italiano, Dept Cardiol, Milan, Italy