There are multiple definitions:

1. peak expiratory flow(English)

   • Respiratory system

2. pulsed electric field(English)

   • CP, HHP, PL, UV, VBNC
   • Food microbiology
   • https://doi.org…micb.2018.02773

3. preserved ejection fraction(English)

   • hyperkalemia and hypokalemia are associated with heightened risk for mortality in patients with heart failure and preserved ejection fraction
   • EF, HFpEF, REF
   • Cardiology, Potassium
   • https://doi.org…ail.2018.03.002