Slaves of the world
When the heart is subdued by the world, meaning when a person is obedient towards the world, wherever that person sees ways of obtaining world's enjoyments, will follow those ways. This means whatever his/her inner desires are, he/she will follow those and make that person to become obedient to his/her inner desires. Imam Ali (A.S) said: This type of person is someone who if sees a thing which his/her heart likes and is in others hands, will be humble towards them and will become totally obedient towards them in order to get to that thing \[1].
[1] Rasa'el Bandegy (Farsi Edition) by Ayatollah Mojtaba Tehrani, page 105.