The heartbeat background sound effect is the reason I usually try to avoid drinking Cat Potions in the Witcher 2. It is a somewhat annoying sound that can drown out other sounds (like combat sounds that can help you predict monster/enemy attacks) if the sounds settings aren’t set properly. It serves no purpose in the game and makes little sense in the game itself. Main character Geralt can only hear his own heartbeat, not that of other people. Yet the potion allows him to see the veins inside someone’s body, but it doesn’t show his own veins. The potion description also tells you that the potion should help Geralt see better in the dark, but it didn’t say anything about partially taking away his hearing.