GUATIMOSIM LAB William Pu: Boston Childrens Hospital, Harvard Medical School, Boston/USA Jon Lederer:University of Maryland School of Medicine, Baltimore/USA Robert Gros: Robarts Research Institute, London/Canada Thassio Mesquita: Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California Marco Prado and Vania Prado:University of Western Ontario, London/Canada Ivanita Stefanon: Universidade Federal do Espírito Santo, ES/Brasil Helio Salgado: Faculdade de Medicina de Ribeirão Preto, São Paulo/Brasil