Campy shift cables have slightly smaller heads than Shimano's and using Shimano size cables in Campy brifters can lead to a nasty jam that very difficult to remove in the future. Other than that and within a given brand, the cables are interchangeable.

BTW, if you do get a Shimano or Jagwire teflon coated cables, be sure to scrape away the coating where the derailleur pinch bolt goes. Otherwise I promise you it will slip and the shifting will get unreliable until you clean it off and reclamp.