Human atrial trabeculae: an experimental preparation for studying myocardial response to perioperative manipulations.

Trabeculae taken from discarded human right atrial specimens during cardiac surgery provide a useful preparation for studies in myocardial physiology and pharmacology. Three extrinsic measurements that have a marked effect on contraction of this preparation are temperature, stimulation frequency and calcium ion (Ca2+) concentration. There is a large decline in developed force below 30 degrees C. The optimal stimulation frequency (temperature 34 degrees C, Ca2+ concentration 2.5 mM) is 1 Hz. The Ca2+ level required to give half maximal force development is 2.0 mM. In a series of 46 atrial trabeculae (approximately 1 mm in diameter) from 33 patients, the authors found a mean contraction tension of 1.37 +/- 0.09 g/mm2 (+/- standard error) (temperature 34 degrees C, stimulation frequency 1 Hz, pH 7.4, Ca2+ concentration 2.5 mM) at maximum force. The preparation appears to have great potential for the study of perioperative manipulation on myocardial function.