Quatrefoil reentry is a type of cardiac arrhythmia that consists of two adjacent figure-of-eight reentrant circuits.

Quatrefoil reentry was predicted by bidomain

Bidomain

The bidomain model is a mathematical model of the electrical properties of cardiac muscle that takes into account the anisotropy of both the intracellular and extracellular spaces.The bidomain model was developed in the late 1970s....

 simulations in 1991

and observed experimentally in 1999.

Quatrefoil reentry can be induced by stimulating the heart through a single electrode twice, with the second stimulus timed near the end of the refractory period of the first action potential. If the second stimulus is a cathode, the wave fronts propagate initially parallel to the myocardial fibers; if it is an anode, the wave fronts propagate initially perpendicular to the fibers. Quatrefoil reentry can be understood qualitatively using a simple cellular automaton

Cellular automaton

A cellular automaton is a discrete model studied in computability theory, mathematics, physics, complexity science, theoretical biology and microstructure modeling. It consists of a regular grid of cells, each in one of a finite number of states, such as "On" and "Off"...

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