torsade vs torsades de pointes

torsade

noun
  • torsade de pointes 

  • A decoration, especially on hats, made from twisted ribbon 

torsades de pointes

noun
  • A polymorphic ventricular tachycardia, predisposing to sudden cardiac death and more likely to occur during prolongations of the QT interval. 

How often have the words torsade and torsades de pointes occurred in a corpus of books? (source: Google Ngram Viewer )