title: Use of the sinus P wave in diagnosing electrocardiographic limb lead misplacement not involving the right leg (ground) lead.
abstract: No general approach has been established for the diagnoses of the various types of electrocardiograms of limb lead misplacement not involving the right leg (ground) lead. We have developed a 3-step algorithm for such differential diagnosis that can be applied without having to rely on the comparison with a reference electrocardiogram. It is based on the observation that the frontal plane sinus P vector loop is almost invariably inscribed counterclockwise. The 5 types of electrocardiograms of limb lead misplacement can be differentiated according to the P wave axis, the location of the lead aVR in the electrocardiogram, and specifically any apparent reversal of the direction of inscription of the frontal plane P vector loop due to lead misplacement. Characteristic limb lead P wave patterns provide 6 signs capable of inferring from the electrocardiogram alone the direction of inscription about 94% of the time. P wave axis itself is diagnostic in an additional 4%.
authors.affiliation: Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115-5491, USA. kho@caregroup.harvard.edu
authors.forename: K K
authors.initials: KK
authors.lastname: Ho
authors.forename: S K
authors.initials: SK
authors.lastname: Ho
mesh_terms: D000465:Algorithms; D003951:Diagnostic Errors; D004562:Electrocardiography / Q000379:methods*; D004566:Electrodes; D006801:Humans; D007866:Leg / Q000502:physiology; D014672:Vectorcardiography