The Collaborative International Dictionary of English v.0.48:

Cardiac \Car"di*ac\, a. [L. cardiacus, Gr. ?, fr. ? heart: cf.
   F. cardiaque.]
   1. (Anat.) Pertaining to, resembling, or hear the heart; as,
      the cardiac arteries; the cardiac, or left, end of the
      stomach.
      [1913 Webster]

   2. (Med.) Exciting action in the heart, through the medium of
      the stomach; cordial; stimulant.
      [1913 Webster]

   Cardiac passion (Med.) cardialgia; heartburn. [Archaic]

   Cardiac wheel. (Mach.) See Heart wheel.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cardiac \Car"di*ac\ n. (Med.)
   A medicine which excites action in the stomach; a cardial.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cardiac
    adj 1: of or relating to the heart; "cardiac arrest"

Moby Thesaurus II by Grady Ward, 1.0:

18 Moby Thesaurus words for "cardiac":
   abdominal, anal, appendical, cecal, colic, colonic, coronary,
   duodenal, enteric, gastric, ileac, intestinal, jejunal,
   mesogastric, pyloric, rectal, splanchnic, visceral