In this paper we perform a consistency investigation for the initialization of Monocular Simultaneous Localization and Mapping filters by utilizing an existing closed-form solution for metric velocity, landmark distance and attitude determination. This closed-form solution offers a consistent initial estimate for the state as well as the covariance of the considered system. The resulting initialization equations solely rely on monocular images and measurements of an inertial measurement unit (IMU) with 9 degrees of freedom. Furthermore they do not require any prior knowledge or assumptions about the estimates or the surrounding static environment. Based on these analytical expressions, we will derive conditions which are required in order to gain consistent initial estimates. The actual consistency, the accuracy of the initial state and the properties of the initial covariance will then be discussed thoroughly on the basis of simulated experiments.