Board Thread:Warhammer 40k General Discussion/@comment-5846164-20130527133906/@comment-8881468-20130619194959

jeebus read the article or the codex maybe?

" Its function is to enhance the performance of an Astartes by supplying more oxygen and nutrients to the muscles by increasing blood flow well-beyond that capable for even the most fit normal human being."

then next passage goes along the lines of: if the main heart fails, the secondary one is enough to keep the astartes alive until he can be treated.

thus Lukas will receive less nutrients and oxygen than other Astartes thanks to not having this secondary heart, meaning that he does not have as much power at his command, nor as much stamina as others.