pitter-patter vs pulsating

pitter-patter

noun

  • A soft, percussive sound, as of tiny feet, or of rain on a rooftop. 

pulsating

noun

  • A pulsation. 

adj

  • Very exciting. 

How often have the words pitter-patter and pulsating occurred in a corpus of books? (source: Google Ngram Viewer )