Apparatus, including a flexible insertion tube, having a distal segment that is configured to be inserted into a body organ. A plurality of elastic branches are connected to the distal segment of the insertion tube at different, respective locations and extend transversely away from the insertion tube at the respective locations. There are one or more respective electrodes disposed on each of the elastic branches and there are conductors traversing the elastic branches so as to couple the electrodes to the insertion tube.
