TiN surfaces were obtained on platinum-10% iridium as well as titanium pacing electrodes by Arc Ion Plating and Ion Nitriding, under different experimental conditions. The electrical performances of the different electrodes obtained were compared using a normalized cell configuration. The electrical response of the system was further examined by analyzing the shape of the pulse response observed during the lead impedance determination, as well as, by using cyclic voltammetry and impedance spectroscopy. The increase in the electrode surface-to-geometric area ratio, associated with dark TiN coatings, resulted in substantially lower lead impedance values. The electrical characterization results obtained were related to the depolarization of the electrical interface when compared to the uncoated electrodes. (c) 2006 Springer Science + Business Media, Inc.