An implantable medical device for stimulating electrically excitable tissue within a patient, and more particularly relates to such a system having a pulse generator and a lead. The lead includes a first set of electrodes including at least three electrodes. The lead also includes a second set of electrodes including at least first, second and third electrodes. The first and second electrodes are positioned on opposite sides of an imaginary longitudinal axis that passes through the center of the third electrode. The second set of electrodes is located at or nearer to the proximal portion of the lead relative to the location of the first set of electrodes.