Minimally invasive cardiac catheter ablation procedures require effective visualization of the relevant heart anatomy and electrophysiology (EP). In a typical ablation procedure, the visualization tools available to the cardiologist include bi-plane fluoroscopy, real-time ultrasound, and a coarse 3D model which gives a rough representation of cardiac anatomy and electrical activity. Recently, there has been increased interest in incorporating detailed, patient specific anatomical data into the cardiac ablation procedure. We are currently developing a prototype system which both integrates a patient specific, preoperative data model into the procedure as well as fuses the various visualization modalities (i.e. fluoroscopy, ultrasound, EP) into a single display. In this paper, we focus on two aspects of the prototype system. First, we describe the framework for integrating the various system components, including an efficient communication protocol. Second, using a simple two-chamber phantom of the heart, we demonstrate the ability to integrate preoperative data into the ablation procedure. This involves the registration and visualization of tracked catheter points within the cardiac chambers of the preoperative model.