BASE-Bielefeld Academic Search Engine Redalyc Revista Costarricense de Cardiología, Volume: 11, Issue: 2, Pages: 03-09, Published: DEC 2009 Revista Argentina de Cardiología, Vol 77, Iss 4, Pp 298-305 (2009) Revista Uruguaya de Cardiología, Volume: 24, Issue: 2, Pages: 142-151, Published: SEP 2009