matter of life and death vs myocardial infarct

matter of life and death

noun
  • Something whose outcome could result in either someone's survival or their death 

  • An extremely urgent matter. 

myocardial infarct

noun
  • Synonym of myocardial infarction 

How often have the words matter of life and death and myocardial infarct occurred in a corpus of books? (source: Google Ngram Viewer )