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.
KeywordsCombustion Propa Norepinephrine Resis Epinephrine
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- Cranefield, P.F.: The conduction of the cardiac impulse. The slow response and cardiac arrhythmias. Mount Kisco, N.Y., Futura, pp. 185, 1975.Google Scholar
- Cranefield, P.F.: Does spontaneous activity arise from phase 4 depolarization or from triggering? In: The Sinus Node. Structure, Function and Clinical Relevance, Bonke, F.I.M., ed., Martinus Nijhoff, The Hague, pp. 348–336, 1978.Google Scholar
- Gadsby, D.C., Wit, A.L. and Cranefield, P.F.: Overdrive suppression of triggered atrial tachycardia arising in the canine coronary sinus. (Abstr.) Amer. J. Cardiol., 43: 374, 1979..Google Scholar
- Mayer, A.G.: Rhythmical pulsation in Scyphomedusae: II. In: Papers from the Tortugas Laboratory of the Carnegie Institution of Washington. I: 113–131 (Carnegie Institution of Washington, Publication No. 102, part VII), 1908.Google Scholar
- Mines, G.R.: On circulating excitations in heart muscles and their possible relation to tachycardia and fibrillation. Trans. Roy. Soc. Can. Ser. 3, sec. 4, 8: 43–52, 1914.Google Scholar
- Vassalle, M., Cummins, M., Castro, C. and Stuckey, J.H.: The relationship between overdrive suppression and overdrive excitation in ventricular pacemakers in dogs. Circ. Res., 38: 367–374, 1975.Google Scholar
- West, T.C.: Effects of chronotropic influences on subthreshold oscillations in the sino-atrial node. In: The Specialized Tissues of the Heart, Paes de Carvalho, A., de Mello, W.C. and Hoffman, B.F., eds., Amsterdam, Elsevier, pp. 81–94, 1961.Google Scholar
- Wit, A.L. and Cranefield, P.F.: Triggered and automatic activity in the canine coronary sinus. Circ. Res., 41: 435–455, 1977.Google Scholar