Metaphor or Hyperbole?

Here's an engineering term applied in a less convential way (I like to call that "original"):

In those moments after he first saw her he was overwhelmed by her beauty. His heart ran faster and faster until it began to cavitate. He was in love.

Is it a metaphor to apply a pumping term to what is in fact, a pump? Since hearts don't generally cavitate due to their ingenious design and the ample suction head available, I guess it's hyperbole.