  Excitable media are a generic class of models used to simulate a wide variety
of natural systems including cardiac tissue. Propagation of excitation waves in
this medium results in the formation of characteristic patterns such as
rotating spiral waves. Instabilities in these structures may lead to
spatiotemporal chaos through spiral turbulence, which has been linked to
clinically diagnosed conditions such as cardiac fibrillation. Usual methods for
controlling such phenomena involve very large amplitude perturbations and have
several drawbacks. There have been several recent attempts to develop
low-amplitude control procedures for spatiotemporal chaos in excitable media
which are reviewed in this paper. The control schemes have been broadly
classified by us into three types: (i) global, (ii) non-global
spatially-extended and (iii) local, depending on the way the control signal is
applied, and we discuss the merits and drawbacks for each.
