A method for processing a chain reaction codes includes first selecting a source symbol which is associated an output symbol of degree two or higher, and subsequently deactivating the selected source symbol in an attempt to produce an output symbol of degree one. A second antenna element is substantially co-planar with the first antenna element, the second antenna element having first and second ends spaced apart by a surface thereof. Finally, a first pacing pulse is delivered to a number of locations within the atria when the first atrial activation is detected.