1 Pediatric Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico and Department of Clinical Sciences and Community Health, Universita degli Studi di Milano, Milan, Italy.
2 Università della Svizzera Italiana, Lugano, Switzerland.
3 Department of Pediatric Cardiology, Inselspital, University Children's Hospital of Bern, Bern, Switzerland.
4 Department of Pediatrics, Inselspital, Universitatsspital Bern, Bern, Switzerland.