Leads having electrodes implanted in or about the heart have been used to reverse certain life threatening arrhythmia, or to stimulate contraction of the heart. Electrical energy is applied to the heart via an electrode to return the heart to normal rhythm. Leads are usually positioned on or in the ventricle or the atrium and the lead terminal pins are attached to a pacemaker or defibrillator which is implanted subcutaneously.
Some factors that affect electrode performance include polarization at the electrode/tissue interface, electrode capacitance, sensing impedance, and voltage threshold. What is needed is electrodes that are constructed to optimize these factors as needed.