Intra-cardiac mapping and ablating

Systems, methods, and devices allow percutaneous mapping, orientation and/or ablation in bodily cavities or lumens. Such may include a structure that is percutaneously positionable in a cavity, such as an intra-cardiac cavity of a heart. Transducers carried by the structure are responsive to blood flow. For example, the transducers may sense temperature, temperature being related to convective cooling caused by blood flow. A controller discerns positional information or location, based on signals from the transducers. For example, blood flow may be greater and/or faster proximate a port in cardiac tissue than proximate tissue spaced from the port. Position information may allow precise ablation of selected tissue, for example tissue surround a port in the intra-cardiac cavity.