  The concept of asymmetric entanglement-assisted quantum error-correcting code
(asymmetric EAQECC) is introduced in this article. Codes of this type take
advantage of the asymmetry in quantum errors since phase-shift errors are more
probable than qudit-flip errors. Moreover, they use pre-shared entanglement
between encoder and decoder to simplify the theory of quantum error correction
and increase the communication capacity. Thus, asymmetric EAQECCs can be
constructed from any pair of classical linear codes over an arbitrary field.
Their parameters are described and a Gilbert-Varshamov bound is presented.
Explicit parameters of asymmetric EAQECCs from BCH codes are computed and
examples exceeding the introduced Gilbert-Varshamov bound are shown.
