A simple electronic circuit for determining the twitch force and resting force of small heart muscle preparations.

The twitch of small preparations of heart muscle is often weak and difficult to record accurately during an experiment. Measurement of small twitch forces can also be handicapped by minor disturbances in the experimental chamber. We describe here a simple electronic circuit that is useful for detecting small changes of twitch force during experimental interventions. Using this circuit, the twitch force signal can be recorded on relatively high gain and changes of twitch force can be observed that might otherwise go undetected.