  Using the Witten-Sakai-Sugimoto model in the D0-D4 background, we
holographically compute the vacuum decay rate of the Schwinger effect in this
model. Our calculation contains the influence of the D0-brane density which
could be identified as the $\theta$ angle or chiral potential in QCD. Under the
strong electromagnetic fields, the instability appears due to the creation of
quark-antiquark pairs and the associated decay rate can be obtained by
evaluating the imaginary part of the effective Euler-Heisenberg action which is
identified as the action of the probe brane with a constant electromagnetic
field. In the bubble D0-D4 configuration, we find the decay rate decreases when
the $\theta$ angle increases since the vacuum becomes heavier in the present of
the glue condensate in this system. And the decay rate matches to the result in
the black D0-D4 configuration at zero temperature limit according to our
calculations. In this sense, the Hawking-Page transition of this model could be
consistently interpreted as the confined/deconfined phase transition.
Additionally there is another instability from the D0-brane itself in this
system and we suggest that this instability reflects to the vacuum decay
triggered by the $\theta$ angle as it is known in the $\theta$-dependent QCD.
