  By using a heavy chiral unitary approach, we study the $S$ wave interactions
between heavy vector meson and light pseudoscalar meson. By searching for poles
of the unitary scattering amplitudes in the appropriate Riemann sheets, several
$1^+$ heavy states are found. In particular, a $D^*K$ bound state with a mass
of $2.462\pm0.010$ GeV which should be associated with the recently observed
$D_{s1}(2460)$ state is obtained. In the same way, a $B^*{\bar K}$ bound state
($B_{s1}$) with mass of $5.778\pm0.007$ GeV in the bottom sector is predicted.
The spectra of the dynamically generated $D_1$ and $B_1$ states in the $I=1/2$
channel are also calculated. One broad state and one narrow state are found in
both the charmed and bottom sectors. The coupling constants and decay widths of
the predicted states are further investigated.
