I have created a very simple Processing sketch that works with the Sample EKG Shield Arduino sketch. I hope this will save someone else some time.
https://github.com/fractalbass/ekg_field_monitor (https://github.com/fractalbass/ekg_field_monitor)
The repo also contains a sample screen capture of how it looks. It is basically a 2x3 grid of graphs, each section of the grid corresponds to one of the 6 channels of the shield.
Best Regards,
Miles Porter
mporter@paintedharmony.com