A hearty communication (6)
I believe the answer is:
artery
'communication' is the definition.
(thesaurus)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for artery that I've seen before include "vessel carrying vital supply" , "Principle channel of circulatory system" , "Felt amazement" , "blood line" , "main course" .)