Source : Webster's Revised Unabridged Dictionary (1913)

Palpitate \Pal"pi*tate\, v. i. [imp. & p. p. {Palpitated}; p.
   pr. & vb. n. {Palpitating}.] [L. palpitare, palpitatum, v.
   intens. fr. pappare. See {Palpable}.]
   To beat rapidly and more strongly than usual; to throb; to
   bound with emotion or exertion; to pulsate violently; to
   flutter; -- said specifically of the heart when its action is
   abnormal, as from excitement.

Source : WordNet®

palpitating
     adj : having a slight and rapid trembling motion; "palpitant
           movements rather than violent eruptions"; "my
           palpitating heart" [syn: {palpitant}]