An implantable medical device includes an elongated tubular body having opposed proximal and distal end portions and defining a longitudinal axis. The elongated tubular body includes an interior lumen extending therethrough. A plurality of axially spaced apart electrode rings are operatively associated with the distal end portion of the tubular body. The electrode rings are formed from at least one of bismuth or pyrolytic graphite. A plurality of electrical conductors extend through the interior lumen of the tubular body. Each of the electrical conductors is operatively associated with a respective one of the plurality of electrode rings. The electrical conductors are formed from at least one of bismuth or carbon fiber.
