Electrophysiology mapping and visualization systems are described herein where such devices may be used to visualize tissue regions as well as map the electrophysiological activity of the tissue. Such a system may include a deployment catheter and an attached hood deployable into an expanded configuration. In use, the imaging hood is placed against or adjacent to a region of tissue to be imaged in a body lumen that is normally filled with an opaque bodily fluid such as blood. A translucent or transparent fluid, such as saline, can be pumped into the imaging hood until the fluid displaces any blood, thereby leaving a clear region of tissue to be imaged via an imaging element in the deployment catheter. A position of the catheter and/or hood may be tracked and the hood may also be used to detect the electrophysiological activity of the visualized tissue for mapping.