Cardiac Arrest!

Cardiac Arrest! is an achievement/trophy for Fallout: New Vegas add-on Old World Blues.

In order to unlock this trophy/Achievement, the courier must get the "Stealth suit Mk II" in the X-13 Research Facility, Which is a part of a side quest: [http://fallout.wikia.com/wiki/X-13:_Attack_of_the_Infiltrator! "X-13: Attack of the Infiltrator!"].