Board Thread:Warhammer 40k General Discussion/@comment-5846164-20130527133906/@comment-7186329-20130612171709

Replacing your heart with a grenade? HOly... that`s the Space Wolves for ya...

Neithan02 is correct, however the second heart is vital to drastically improving the capabilities of an astartes and doesn`t just act as a fail safe. With that in mind the capabilities of any astartes without that second heart would be greatly reduced, if not halved. That stasis grenade is  gonna go off soon...