Visualization and treatment of tissue regions via percutaneous access methods and devices are described herein. The system may include a deployment catheter and an expandable imaging hood. In use, the hood may be introduced from outside the patient body through a percutaneous incision and advanced through a subxiphoid pathway, for example, to the heart where entry may be accomplished via an incision through the left atrial appendage. Once within the heart, the hood can be advanced to any chamber to visualize and/or treat tissue by placing the hood against the tissue to be imaged and pumping translucent fluids into the 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. Additionally, any number of therapeutic tools can also be passed through the deployment catheter and into the imaging hood for treating the tissue of interest.
