The best replacement for ventricles is atria.

The best alternatives to ventricles are rated as following:
★★★★★  atria
★  atrium
★  subarachnoid space
  auricles

Your alternative for ventricles is not listed? Suggest!
Speaking about ventricles, one probably shouldn't forget about shunt.

Other search terms related to ventricles and their ratings are:
★★★★★ shunt
★ hypertrophy of the ventricles
You have in mind a companion for ventricles and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of ventricles in all years. Click on graph for more.
ventricles
atria
atrium