In the heart, perturbations can induce wave breakups that lead to spiral waves (arrhythmia) 8, which can further evolve into life-threatening dynamics with spatiotemporally chaotic waves (fibrillation) 9. Disturbances in these excitable patterns can cause severe, and even fatal, impacts on the organism. Other examples include electrophysiological waves in the cerebral neocortex 6 and mammalian hearts, where the latter maintain the contractility and cardiovascular blood circulation 7. An example is PIP3-lipid dynamics in the membranes of Dictyostelium cells regulating cell migration 4, 5. In biological systems in particular, these dynamics have important regulatory functions. Spatiotemporal dynamics in excitable media appear in a wide and diverse range of systems 1, 2, 3. These findings provide insights into a broad class of complex periodic systems, with particular impact to the control and understanding of heart diseases. We combined a novel signaling over-sampling technique with a multi-dimensional Fourier analysis, showing that line defects can translate, merge, collapse and form stable singularities with even and odd parity while maintaining a stable oscillation of the spiral wave in the tissue. Through in vitro experiments of heart tissue observation, we reveal the spatiotemporal dynamics of line defects in rotating spiral waves. However, it remains unknown if the line defects are static or dynamically changing structures in heart tissue. Previous studies suggested that line defects (nodal lines) play a critical role in stabilizing those undesirable patterns. In the heart, excitable waves can form complex oscillatory and chaotic patterns even at an abnormally higher frequency than normal heart beats, which increase the risk of fatal heart conditions by inhibiting normal blood circulation.
Spatiotemporal pattern formation governs dynamics and functions in various biological systems.
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