title: P-wave dispersion: an update.
abstract: P-wave dispersion (PWD, Pd or Pdis) is a noninvasive electrocardiographic (ECG) marker for atrial remodeling and predictor for atrial fibrillation (AF). PWD is defined as the difference between the widest and the narrowest P-wave duration recorded from the 12 ECG leads. Increased P-wave duration and PWD reflect prolongation of intraatrial and interatrial conduction time with lack of a well-coordinated conduction system within the atrial muscles, with inhomogeneous, asynchronic, pro-inflammatory and anti-inflammatory effect mediated by interleukin-6 (IL-6) in patients with the CG + GG genotype IL-6 -634C/G polymorphism [1] and discontinuous propagation of sinus impulses mainly between the left and right atria, interstitial/extracellular fibroblast activation and collagen deposition with fibrosis (via TGF-β) in atrial tissue, insufficient blood supply, significant not isotropic myoelectric activity, and thin wall thickness and consequent expansion tendency all well-known electrophysiological characteristics in patients with atrial arrhythmias and especially paroxysmal atrial fibrillation (PAF) [2].
authors.affiliation: Design of Studies and Scientific Writing Laboratory in the ABC Medicine Faculty, Santo André, São Paulo, Brazil. Electronic address: riera@uol.com.br.
authors.forename: Andrés Ricardo
authors.initials: AR
authors.lastname: Pérez-Riera
authors.affiliation: Design of Studies and Scientific Writing Laboratory in the ABC Medicine Faculty, Santo André, São Paulo, Brazil; Program in Molecular and Integrative Physiological Sciences (MIPS), Department of Environmental Health, Harvard T.H. Chan School of Public Health, USA.
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: de Abreu
authors.affiliation: Coronary Center of the Messejana Hospital Dr. Carlos Alberto Studart Gomes, Fortaleza, Ceará, Brazil.
authors.forename: Raimundo
authors.initials: R
authors.lastname: Barbosa-Barros
authors.affiliation: Electrocardiology Sector, Central Institute of Clínicas Hospital, Faculty of Medicine, University of São Paulo (HCFMUSP), Brazil.
authors.forename: José
authors.initials: J
authors.lastname: Grindler
authors.affiliation: Electrocardiology Sector, Central Institute of Clínicas Hospital, Faculty of Medicine, University of São Paulo (HCFMUSP), Brazil.
authors.forename: Acácio
authors.initials: A
authors.lastname: Fernandes-Cardoso
authors.affiliation: Division of Cardiology, Queen's University, Kingston, Ontario, Canada.
authors.forename: Adrian
authors.initials: A
authors.lastname: Baranchuk
keywords: Interatrial block; Intraatrial block; P-wave dispersion; P-wave duration; Paroxysmal atrial fibrillation