The Collaborative International Dictionary of English v.0.48:

Pericardiac \Per`i*car"di*ac\, Pericardial \Per`i*car"di*al\, a.
   (Anat.)
   Of or pertaining to pericardium; situated around the heart.
   [1913 Webster]

   Pericardial fluid (Physiol.), a serous fluid of a pale
      yellow color contained in the pericardium.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pericardial
    adj 1: located around the heart or relating to or affecting the
           pericardium; "pericardial space" [syn: pericardial,
           pericardiac]