Devices, instruments and tools for minimally invasive surgical procedures. Port devices and methods for hemostatically sealing and providing a port through a tissue wall that interfaces with a fluid containing chamber, by minimally invasive techniques. Assemblies, instruments and methods for minimally invasive access to and through a tissue wall that interfaces with a fluid containing chamber, and for visualizing same. Instruments, assemblies and methods for minimally invasive surgical procedures, including ablation.