In this paper, we introduce a new type of curvature tensor named H-curvature
tensor of type (1, 3) which is a linear combination of conformal and
projective curvature tensors. First we deduce some basic geometric
properties of H-curvature tensor. It is shown that a H-flat Lorentzian
manifold is an almost product manifold. Then we study pseudo H-symmetric
manifolds (PHS)n (n > 3) which recovers some known structures on Lorentzian
manifolds. Also, we provide several interesting results. Among others, we
prove that if an Einstein (PHS)n is a pseudosymmetric (PS)n, then the scalar
curvature of the manifold vanishes and conversely. Moreover, we deal with
pseudo H-symmetric perfect fluid spacetimes and obtain several interesting
results. Also, we present some results of the spacetime satisfying
divergence free H-curvature tensor. Finally, we construct a non-trivial
Lorentzian metric of (PHS)4.