The cards were randomly selected. I'm not sure exactly how the heart and mind knew... although given that the mind followed behind the heart, I'm guessing that the mind simply took the heart's cue!
Oh, I just found this... which seems to suggest that the pre-stimulus emotional responses to non-local objects and events is based on the heart connecting to knowledge about those objects/events that is only held in a domain of quantum holographical information. I guess at the end of the day they are all saying that the experiments proved accurate heart and mind responses to non-local objects and events and that the only way the heart and mind could have known is by being connected to a body of knowledge that held implicit knowledge about these objects and events... and that this knowledge was outside of the construct of time and space because we can't access it consciously. But seemingly, our hearts are already connected to it. It's quite something to try to get one's head around! I'd love to find more articles about it to read more about exactly what the experiment involved.
The Psychophysiology Of Intuition: A Quantum-Holographic Theory Of Nonlocal Communication