big sleep vs heart attack

big sleep

noun
  • Death. 

heart attack

noun
  • Death or failure. 

  • An acute myocardial infarction, sometimes fatal, caused by the sudden occurrence of coronary thrombosis, which obstructs the blood supply to the heart and leads to necrosis of heart muscle tissue. 

How often have the words big sleep and heart attack occurred in a corpus of books? (source: Google Ngram Viewer )