The present disclosure provides a medical device comprising a restraining assembly configured to assist in restraining a catheter shaft in a deflected configuration. The resistance assembly may include an inner restraining assembly and an outer restraining assembly configured to engage one another and create normal and frictional resistances therebetween sufficient to prevent unintentional and/or undesired proximal, retracting movement of an actuator, and thus, to prevent changes in a desired deflected configuration of the catheter shaft. In one embodiment, the restraining assembly is configured to allow for temporary, i.e., reversible, restraining of the catheter shaft in the deflected configuration.