Our hosts, Drs. Bouman and Jongsma, have asked me to summarize the different mechanisms by which spontaneous activity might arise in a cluster of cells, adding that, in their view, a cluster of cells must be taken as the model rather than the single cell to allow for the possible role of reentry as a mechanism for spontaneous activity. In response to their suggestion, I will point out a few ways in which a cell or a collection of cells could serve as a pacemaker and consider some ways in which the rate of such a pacemaker might be varied.
KeywordsRhythmic Activity Pacemaker Cell Atrial Cell Purkinje Fiber Circus Movement
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