I am currently working through a problem concerning the massive vector field. Amongst other things I have already calculated the equations of motion from the Lagrangian density $$\mathcal{L} = - \frac{1}{4} F_{\mu\nu} F^{\mu\nu} + \frac{1}{2} m^2 A^\mu A_\mu,$$ where $F_{\mu\nu} = \partial_\mu A_\nu - \partial_\nu A_\mu$, which are \begin{align} \partial_\mu F^{\mu\nu} + m^2 A^\nu = 0. \end{align} Here the sign convention is $(+,-,-,-)$.
The problem then leads me through some calculations to end up with a Hamiltonian. Basically one defines the canonical momentum and from the equations of motion it follows that $A^0 = \frac{1}{m^2} \partial_i \Pi_i $ (where from here on summation convention is used for repeated indices regardless of their position). Basically this means that $A^0$ is not a dynamical variable and can be eliminated in terms of $\Pi_i$. By using this and the fact that $\Pi_i (x) = \partial_0 A^i (x) + \partial_i A^0 (x)$, one can find the following Hamiltonian:
\begin{align} H = \int d^3 \vec{x}\; \mathcal{H} = \int d^3 \vec{x}\; \left(\frac{1}{2} \Pi_i \Pi_i + \frac{1}{2m^2} \partial _ i \Pi_i \partial _j\Pi_j + \frac{1}{2} \partial_i A^j (\partial_i A^j - \partial_j A^i ) + \frac{m^2}{2} A^i A^i \right). \end{align}
Long story short: I am now supposed to calculate the Hamiltonian equations of motion from this and show that they lead to the same ones that I got from the Lagrangian.
Now it is not clear to me what form the Hamiltonian equations of motion should have here. The way they are written on Wikipedia (https://en.wikipedia.org/wiki/Hamiltonian_field_theory) with only the time derivatives on the left hand side won't lead to the same equations of motion, right?
EDIT: Thanks to the answer by GRrocks I think I got it now. \begin{align} -\partial_0 \Pi^k & = - \partial_0 \left(\partial_0 A^k + \partial_k A^0 \right) =\frac{\delta \mathcal{H}}{\delta A^k} = \\ &= m^2 A^k - \frac{1}{2} \partial_i \partial_i A^k - \frac{1}{2}\partial_i \partial_i A^k + \frac{1}{2} \partial_j\partial_k A^j - \frac{1}{2} \partial_j\partial_k A^j = \\ &= m^2 A^k - \partial_i \partial_i A^k + \partial_j\partial_k A^j \end{align} and so \begin{align} \partial_0 \partial_0 A^k - \partial_i \partial_i A^k + m^2 A^k + \partial_0 \partial_k A^0 + \partial_i \partial_k A^i = 0 \end{align} which is indeed equal to the Lagrangian equations of motion. My question now is what the equations $\partial_0 A ^i = \frac{\delta \mathcal{H}}{\delta \Pi_i} $ are if I already get the full Lagrangian equations of motion with $-\partial_0 \Pi^k =\frac{\delta \mathcal{H}}{\delta A^k} $. What am I missing?