The occurrence of Winfree turbulence is currently regarded as one of the principal mechanisms underlying cardiac fibrillation. We develop a local stimulation method that suppresses Winfree turbulence in three-dimensional excitable media. We find that Winfree turbulence can be effectively suppressed by locally injecting periodic signals to only a very small subset (around some surface region) of total space sites. Our method for the first time demonstrates the effectiveness of local low-amplitude periodic excitations in suppressing turbulence in 3D excitable media and has fundamental improvements in efficiency, convenience, and turbulence suppression speed compared with previous strategies. Therefore, it has great potential for developing into a practical low-amplitude defibrillation approach.

Winfree turbulence is a chaotic wave pattern developing through negative-tension instability of scroll wave filaments in three-dimensional weak excitable media. Here, we investigate the response of Winfree turbulence to a spatiotemporal forcing in the form of a traveling-wave modulation of the medium excitability. It is shown that turbulent waves can be suppressed much more rapidly by this method, in comparison with the space-uniform modulation of the medium excitability. Since the occurrence of Winfree turbulence is currently regarded as one of the possible mechanisms underlying cardiac fibrillation, this method turns out to be suggestive of a possible low-amplitude defibrillation approach.

Under the weak deformation approximation, the motion of rigidly rotating spirals induced by periodic and noisy illuminations are investigated analytically. We derive an approximate but explicit formula of the spiral drift velocity directly from the original reaction-diffusion equation. With this formula we are able to explain the main features in the periodic and noisy illuminations induced spiral drift problems. Numerical computations of the Oregonator model are carried out as well, and they agree with the main qualitative conclusions of our analytical results.