[1.8.9] Get held item of player on server?

I want to build a mod which should detect whether a player in the world of a server is holding a certain item in his hands. I tried it with

 if(event.entityPlayer.getHeldItem().getItem() == Items.ender_pearl)

but it didn't work because this is called in the WorldTickEvent and event.entityPlayer is wrong.

I greatly appreaciate every kind of help.