title: Advanced interatrial block: a classic electrocardiogram.
abstract: Interatrial block (IAB; P wave>or=110 ms) indicates conduction delay between the right and left atria. IAB can present as partial or advanced and is denoted on the electrocardiogram (ECG) by bifid or biphasic P waves, respectively, the latter in inferior leads. The importance of IAB cannot be overemphasized due to high prevalence, especially at ages 60 and over, and due to grave associations with atrial flutter and fibrillation as well as congestive heart failure. Thus, we present a classic ECG of the much less common form of IAB, namely advanced IAB, as it serves as an excellent yardstick and teaching tool to help clinicians understand this medical entity thoroughly and to easily recognize this often missed type of block.
authors.affiliation: Division of Aging, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: V
authors.initials: V
authors.lastname: Ariyarajah
authors.forename: D H
authors.initials: DH
authors.lastname: Spodick
mesh_terms: D000368:Aged; D004562:Electrocardiography; D006325:Heart Atria; D006327:Heart Block / Q000175:diagnosis*; D006801:Humans