Where to find everyone with heart problem (5)
I believe the answer is:
earth
'where to find everyone' is the definition.
(I've seen this in another clue)
'heart problem' is the wordplay.
'problem' is an anagram indicator.
'heart' is an anagram of 'EARTH'.
'with' is the link.
(Other definitions for earth that I've seen before include "Mud" , "Our favourite planet" , "Human world" , "Badger's burrow" , "Huge cost" .)