Spiral wave generation in heterogeneous excitable media

Area of Science:

• Cardiovascular Physiology
• Biophysics
• Cellular Electrophysiology

Background:

• Excitable media, like heart tissue, exhibit complex wave propagation dynamics.
• Heterogeneity and reduced cell-to-cell coupling significantly influence these dynamics.
• Understanding these phenomena is crucial for comprehending cardiac arrhythmias.

Purpose of the Study:

• To investigate the impact of reduced intercellular coupling on wave propagation in a heterogeneous excitable medium.
• To observe and characterize the transition from stable plane waves to spiral waves and wave blocking.
• To model these behaviors using a computational approach.

Main Methods:

• Utilized monolayers of chick embryonic heart cells.
• Employed calcium-sensitive fluorescent dyes to visualize wave propagation.
• Administered heptanol to reduce electrical coupling between cells.
• Developed and employed a heterogeneous cellular automaton model.

Main Results:

• Observed three distinct wave propagation behaviors: stable plane waves, plane wave breakup into spiral waves, and wave blocking.
• Demonstrated that reducing intercellular coupling with heptanol induced spiral wave breakup.
• Successfully modeled these phenomena in a modified cellular automaton.

Conclusions:

• Intercellular coupling strength is a critical determinant of wave dynamics in cardiac tissue.
• Reduced coupling can lead to the formation of complex wave patterns, including spiral waves.
• Computational models effectively simulate experimental observations of wave propagation in heterogeneous excitable media.