{HEAD ~ Battery supply ground} is in {TAIL ~ common} with one of the defibrillator leads, and conventional pacers provide pacer pulses with respect to battery ground 
is in
{ HEAD ~ Battery supply ground } is in { TAIL ~ common } with one of the defibrillator leads , and conventional pacers provide pacer pulses with respect to battery ground
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH