The persistence and regularity of electrical activity in whole heart explants.

Abstract

AbstractThe electrical persistence and regularity of 143 chick embryo whole heart explants during nine days in culture is described. Details are given of culturing and surveillance of explants and handling of data. Over 90% of explants showed continuous electrical activity for nearly all of the first three days in culture. This percentage fell 6 % by the end of day three, 6 % during day four, 17 % on day five and more slowly thereafter. These changes possibly reflected inadequacies in the supernatant. The frequency and magnitude of change in the number of active cultures from one 15 second survey to the next slowly increased with a maximum of 1.2 cultures. It seemed that the failure of hearts to produce potentials was usually temporary and occurred in a rhythmic fashion. The difference between consecutive half‐hour averages of the number of cultures showing activity during 15 out of every 20 seconds was relatively high initially, dropped during the second day then rose again. It was always small compared to the total number of cultures involved. Comparisons between the persistence of electrical function in whole heart explants in various supernatants showed that the one used in this study was least inadequate.