In this paper, we present an open architecture that enables the coexistence of and the collaboration between different and heterogeneous clinical decision support models. Clinical decision support can be (and has been) built starting from complementary knowledge representation models, for instance rule-based representations or workflow models to mention just a few. Each model can contribute to the quality and effectiveness of an overall clinical decision support system. Our architecture, Arriclides, enables the integration of a set of representative and quite different models. An evaluation of our prototype implementation shows that such an integration has been achieved while preserving performance and scalability.