Provided is a system and method to target a biological rhythm disorder, such as a heart rhythm disorder. The system and method include processing cardiac signals via a computing device to determine a shape in a region of tissue defined by a source associated with the biological rhythm disorder that migrates spatially on or within the shape, and identifying at least one portion of the tissue proximate to the shape to enable selective modification of the at least one portion of tissue in order to terminate or alter the heart rhythm disorder.