Just read an interesting new book, "Castro's Secrets" by Brian Latell.
It mentions the fact that its training for DGI and other agents training in Cuba to become Cuban and foreign spies included activities on how to beat the polygraph (primarily in order to enable DGI and, during the Cold War, other agents to infiltrate the CIA). If I remember from my reading, the KGB also claimed to have that capability.
The book also includes some very interesting details as to how the DGI essentially beat the CIA at its own game throughout the Cold War. :o