Chaotic Electrical Excitation in the Rat Atrium Revealed by Optical Mapping Studies

Abstract

Spatiotemporal patterns of chaotic electrical excitation-waves in isolated rat atrial preparations were mapped by multiple-site optical recording methods using a multi-element photodiode array together with a fast merocyanine-rhodanine voltage-sensitive dye. Tachycardia-like excitation was evoked by electrical stimulation, then maps of the excitation spread patterns were constructed. In these maps, event-to-event variations are always observed. The event-to-event variations seem to result from the physiologically trivial difference(s) in the initial conditions. This nature of “complex system” strongly supports the idea that tachycardia-like excitation is an example of the functional “self organizing systems”. Although, at the present stage, it is quite difficult to analyze this phenomenon quantitatively, we consider the tachycardia-like excitation observed here as the “physiology-specific attractor”.