2 Spiral waves in the heart
Simulations based on a biophysical model of mammalian ventricular tissue show a snapshot of a spiral-wave solution around a central core (yellow circle). The membrane potential is colour-coded and vertically displaced, and the white lines show two isolines of equal voltage (-10 mV) and equal values of f, a variable determining the flow of calcium ions across the membrane. The intersection of these lines defines the position of the central core, and the spiral wave can be described by the position of this tip.