The Collaborative International Dictionary of English v.0.48:

Heartbroken \Heart"bro`ken\ (-br[=o]`k'n), a.
   Overcome by crushing sorrow; deeply grieved.
   [1913 Webster]

WordNet (r) 3.0 (2006):

heartbroken
    adj 1: full of sorrow [syn: brokenhearted, heartbroken,
           heartsick]