{HEAD ~ a second electrode} having a second pair of bipolar contacts attached to {TAIL ~ the expandable balloon}, 
{ HEAD ~ a second electrode } having a second pair of bipolar contacts attached to { TAIL ~ the expandable balloon } ,
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH