What corrective measures should I use to prevent a rapidly failing heart in my Radnoti Isolated Heart Preparation?

The Radnoti Isolated Heart Preparation is normally very stable and reproducible once the experimenter has gained familiarity with it. A rapid deterioration unexpectedly occurring in two preparations consecutively is a strong indication of a problem. Many times this failure is due to the growth of bacteria and the release of endotoxins into the perfusate. Initial corrective measures should include:

  • a thorough cleaning of the apparatus and replacement of tubing/fittings,
  • replacement of solutions (which have a limited storage life in the refrigerator),
  • a check of the water source,
  • a check of aeration the appropriate gas mixture and pH of the aerated buffer at the normal
  • operating temperature.

Records should be kept of new purchases of substrate and salts. Certain toxic agents used by experimenters may be difficult to clean from the system and may require the use of organic solvents or the removal of tubing after each use, as well as the use of a separate reservoir.


Tubing should be thoroughly pre-rinsed to remove plasticizers and the use of a high-quality silicone or Tygon tubing is recommended. Note that silicone tubing is extremely gas permeable; Oxygen and other gas losses can be considerable. The use of high quality water is essential. Some experimenters use small amounts of EDTA (0.1mM) to chelate trace heavy metals in suspect water supplies, although this is less of a problem with modern multiple cartridge ion-exchange systems.


For more information, please download the Radnoti Trouble Shooting Guide