[Spontaneous periodical arrhythmia in the rabbit isolated right atrium].
Spontaneous periodical changes in the action potentials of myocytes occurring upon alternating of two types of frequencies were registered under the conditions of oxygenated perfusion of an isolated rabbit atrium. Spontaneous changes of the rhythm were elicited by doubling the duration of action potential, and arrhythmia arose upon passing from one frequency to the other. The rhythmicity was interrupted by spontaneous bigeminy and other minicycles. It was shown that spontaneous bigeminy of the atrium being studied is similar to the artificial bigeminy elicited by electrical impulses. These data indicate that the atrium can be considered as a determined nonlinear system. It was assumed that, from the parameters of spontaneous arrhythmia under stable conditions, it is possible to calculate the frequency of spontaneous rhythmical action potential.
Grigaliunene
I
I
Institute of Cardiology, Kaunas Medical University, Kaunas, 3007 Lithuania.
D000200:Action Potentials; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D004558:Electric Stimulation; D006325:Heart Atria / Q000166:cytology / Q000503:physiopathology; D066298:In Vitro Techniques; D009206:Myocardium / Q000166:cytology*; D010477:Perfusion; D011817:Rabbits