A review of bioelectrodes for clinical electrophysiologists

The theory of bioelectrodes describes the rules governing the passage of electrical charge between electrodes and electrolytes. In this review, we explain the basis of bioelectrodes with focus on clinical electrophysiology. The central concept is the double-layer capacitance that forms in the interface between the electrode and tissue. This phenomenon controls charge transfer between electrodes and tissues and contributes to detrimental effects such as electrode polarization and motion artifacts. Many methods critical to the practice of electrophysiology, including fractally coated pacemaker leads, biphasic stimuli, signal filtering, and the use of nonpolarizable electrodes, are devised to mitigate these problems. Our goal is to provide a robust and intuitive background on these topics for practicing electrophysiologists to help them better understand how catheters and leads work and to assist them with optimizing and troubleshooting electrophysiology systems.