An implantable cardiac lead comprises a lead body having a proximal end and a distal end, the proximal end of the lead body carrying a connector assembly connectable to an implantable medical device, and the distal end of the lead body carrying a distal electrode, a proximal electrode and an intermediate electrode positioned between the distal and proximal electrodes. The distal and proximal electrodes are connected together at a node point located within the distal end of the lead body, the node point being electrically connected to a first terminal contact on the connector assembly and the intermediate electrode being electrically connected to a second terminal contact on the connector assembly. Preferably, the intermediate electrode is positioned approximately midway between the distal and proximal electrodes. Also disclosed are a system and a method for differentiating signals generated by a plurality of electrodes carried by a lead body to provide an output signal representative of a second spatial derivative of the generated signals, the output signal being substantially devoid of far-field signals.