The best replacement for flutter is fibrillation.

The best alternatives to flutter are rated as following:
★★★★★  fibrillation
★★★★  atrial fibrillation
★★★  acapella
★★  svt
★★  fib
★  atrial fib
★  palpitation
★  bov
★  ventricular tachycardia
  skip a beat
  atrial tachycardia
  tachycardia
  a-fib
  sinus tachycardia
  afib
  compressor surge
  ventricular fibrillation

Your alternative for flutter is not listed? Suggest!
Speaking about flutter, one probably shouldn't forget about urge to cough.

Other search terms related to flutter and their ratings are:
★★★★★ urge to cough
★ 2 to 1 block
You have in mind a companion for flutter and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of flutter in all years. Click on graph for more.
flutter
fibrillation
atrial fibrillation