Knowledge visualization tools contribute to the efficiency of the processes implemented for the transfer of knowledge. They provide users with intelligible content representations and facilitate access to knowledge by providing dynamic interaction modes. In this paper we presentthetoolMCVGraphVizdedicatedtothevisualizationofgraphsofinteractionsbetween risk factors in the field of cardiovascular diseases. It offers the user an interface to access progressively and dynamically the contents of the graph. MCVGraphViz allows to collect and memorize the actions performed by the user during his navigation in the graph in the form of traces expressed by a path between a starting node and a destination node.