eternal sleep vs heart attack

eternal sleep

noun
  • Death 

  • A magical state of suspended animation, a state of ageless, deathless, everlasting sleep. Well-known examples are Endymion, (the lover of the Greek moon goddess, Selene), and the princess from Sleeping Beauty. 

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 eternal sleep and heart attack occurred in a corpus of books? (source: Google Ngram Viewer )