palpitation vs throb

palpitation

noun
  • An abnormal beating of the heart that may be perceived by the patient, a result of excitement, exertion, or illness. 

throb

noun
  • A beating, vibration or palpitation. 

verb
  • To pound or beat rapidly or violently. 

  • To pulse (often painfully) in time with the circulation of blood. 

  • To vibrate or pulsate with a steady rhythm. 

How often have the words palpitation and throb occurred in a corpus of books? (source: Google Ngram Viewer )