  We compare Chiral Perturbation Theory (ChPT) and the Linear Sigma Model (LSM)
as realizations of low energy QCD for light mesons in a chirally imbalanced
medium. The relations between the low-energy constants of the Chiral Lagrangian
and the corresponding constants of the Linear Sigma Model are established as
well as the expressions for the decay constant of the $\pi$-meson in the medium
and the mass of the $a_0$. In the large $N_c$ count taken from QCD the
correspondence of ChPT and LSM is remarkably good and give a solid ground for
search of chiral imbalance manifestation in pion physics. A possible
experimental detection of chiral imbalance tracks (and therefore a phase with
Local Parity Breaking) in the charged pion decays inside the fireball is
outlined.
