Abstract: A method and apparatus for visibility determination and processing. The method includes receiving at least information associated with a plurality of objects, generating a first plurality of geometric primitives based on at least information associated with the plurality of objects, generating a first plurality of grids based on at least information associated with the first plurality of geometric primitives, and shading the first plurality of grids. The generating a first plurality of grids includes generating a second plurality of grids associated with the first plurality of geometric primitives, selecting a third plurality of grids from the second plurality of grids, and selecting the first plurality of grids from the third plurality of grids.

Abstract: A device for performing minimally invasive closed chest heart massage comprises a support having a plurality of curved, deployable struts, optionally carrying a sheet or inflatable bladder for engaging the pericardium. The struts are delivered to the space between the pericardium and the posterior rib cage in a radially collapsed configuration and deployed radially outwardly with minimum advancement in the axial direction.