dysrhythmia vs dyssynchrony

dysrhythmia

noun
  • A disturbance to an otherwise normal biological rhythm, especially that of the heart. 

dyssynchrony

noun
  • A medical condition wherein the activation of different parts of the heart is improperly synchronized. 

  • A neurological condition wherein auditory stimuli are not processed synchronously. 

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