A device for modulating the autonomic nervous system adjacent a pericardial space to treat cardiac arrhythmia, the device comprising: a treatment source adapted to supply a treatment medium; a catheter having a proximal end and a distal end, the distal end sized for insertion into the pericardial space; a medium delivery assembly, the medium delivery assembly having a proximal end and a distal end, the distal end of the medium delivery assembly positioned by the distal end of the catheter, the distal end of the medium delivery assembly comprising a delivery tip extending away from the distal end of the catheter; a connector operatively coupling the delivery tip of the medium delivery assembly to the treatment source, the delivery tip including an expandable end which is shiftable between a collapsed state and an expanded state, the expandable end connected to a conduit which is either connected to, or forms part of, the connector, characterised in that: the expandable end of the delivery tip is formed from an expandable metal material and includes: (i) a plurality of delivery points for delivering the treatment medium at a plurality of treatment areas within the pericardial space; (ii) an electrode array comprising a plurality of individual electrodes mounted on the expandable end, and wherein the expandable end contains a fluid retention element which is a fabric material, a foam or a sponge. a treatment source adapted to supply a treatment medium; a catheter having a proximal end and a distal end, the distal end sized for insertion into the pericardial space; a medium delivery assembly, the medium delivery assembly having a proximal end and a distal end, the distal end of the medium delivery assembly positioned by the distal end of the catheter, the distal end of the medium delivery assembly comprising a delivery tip extending away from the distal end of the catheter; a connector operatively coupling the delivery tip of the medium delivery assembly to the treatment source, the delivery tip including an expandable end which is shiftable between a collapsed state and an expanded state, the expandable end connected to a conduit which is either connected to, or forms part of, the connector, characterised in that: the expandable end of the delivery tip is formed from an expandable metal material and includes: (i) a plurality of delivery points for delivering the treatment medium at a plurality of treatment areas within the pericardial space; (ii) an electrode array comprising a plurality of individual electrodes mounted on the expandable end, and wherein the expandable end contains a fluid retention element which is a fabric material, a foam or a sponge. the expandable end of the delivery tip is formed from an expandable metal material and includes: (i) a plurality of delivery points for delivering the treatment medium at a plurality of treatment areas within the pericardial space; (ii) an electrode array comprising a plurality of individual electrodes mounted on the expandable end, and (i) a plurality of delivery points for delivering the treatment medium at a plurality of treatment areas within the pericardial space; (ii) an electrode array comprising a plurality of individual electrodes mounted on the expandable end, and wherein the expandable end contains a fluid retention element which is a fabric material, a foam or a sponge.