Cardiac Electrodes and Electrograms: Some New Observations and Concerns

Electrode studies have been performed with dead animal tissue and a variety of other materials immersed in saline solution and compared with studies in the canine heart (live and arrested) in an attempt to delineate both normal and anomalous signals sensed by pacemaker electrodes or obtained during diagnostic electrogram recording of cardiac activity. The data from these studies could be useful for defining the origin of artifacts and a variety of other phenomenon such as “fractured” QRS complexes, acute ST segment elevations, His bundle oscillatory signatures, and unexplained potentials synchronously associated with cardiac events. The studies verify that artifacts can be generated in an electrolyte medium by rubbing electrodes against insulators or biologic materials and by inducing motion between common pole materials of an active electrode system. The studies suggest that some of the grasping electrodes in current clinical use may be subject to self‐generating artifacts associated with cardiac‐induced frictional motion between the constituent materials employed in the electrode design.