The Collaborative International Dictionary of English v.0.48:

Exocardiac \Ex`o*car"di*ac\, Exocardial \Ex`o*car"di*al\, a.
   [Exo- + Gr. kardi`a heart.] (Anat.)
   Situated or arising outside of the heart; as, exocardial
   murmurs; -- opposed to endocardiac.
   [1913 Webster]