His major work is a fully implantable artificial heart called CATO (Corazón Artificial Total Ortotópico - Spanish for Orthotopic Total Artificial Heart), which looks and acts like a real heart. In the development of the CATO, Giambruno worked together with an important team of Uruguayan scientists (cardiac surgeons, engineers, veterinarians and others). The CATO has been tested in cows with good results. Giambruno has earned international patents for his invention. The main factor why the project hasn't been completed yet is the lack of economic resources. For years, the team of scientists has been working very hard and for free, in the living room of Giambruno's apartment in Montevideo.
- "Brave New World". ABC (Australian Broadcasting Corporation). Retrieved 2004-11-04.
- "Uruguayo inventó un corazón artificial". Diario El País, Uruguay. Retrieved 2004-12-31.
- "El corazón artificial es realidad, y es uruguayo". Radio El Espectador, Uruguay. Retrieved 2004-01-28.
- U.S. Patent 6,669,726
- Orthotopic Total Artificial Heart at FreePatentsOnline.com
- Orthotopic Total Artificial Heart Patent