[Method for determination of mechanical activity and electrophysiological properties of isolated human embryonal...

The authors have invented a complex method by which to examine surviving hearts of early human embryos. The method enables testing of mechanical activity of the heart as well as of many electrophysiological parameters, such as spontaneous heart rate, electrical threshold of stimuli, stimulus conduction time, effective refractory phase, and intracellular action potential. --A special transport device was designed for storage and movement of embryonic hearts which were all obtained from cases of legal abortion. A contractility recorder was devised to follow up mechanical heart activity. A variant of the standard micro-electrode technique was developed to measure electrophysiological parameters. This technique has worked extremely well in recording the membrane potential at rest and the intracellular action potential in cells of small embryonic hearts. Also developed was a differentiation unit for direct and convenient measurement of depolarisation velocity of heart cells. The complex method has proved to be particularly suitable to study physiological characteristics relating to the responsiveness of the early human foetal heart to pharmaceuticals.