palpitation vs shudder

palpitation

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

shudder

noun
  • A shivering tremor, often from fear or horror. 

  • A moment of almost pleasurable fear; a frisson. 

verb
  • To vibrate jerkily. 

  • To shake nervously, often from fear or horror. 

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