title: Region [corrected] of slowed conduction acts as core for spiral wave reentry in cardiac cell monolayers.
abstract: Pathophysiological heterogeneity in cardiac tissue is related to the occurrence of arrhythmias. Of importance are regions of slowed conduction, which have been implicated in the formation of conduction block and reentry. Experimentally, it has been a challenge to produce local heterogeneity in a manner that is both reversible and well controlled. Consequently, we developed a dual-zone superfusion chamber that can dynamically create a small (5 mm) central island of heterogeneity in cultured cardiac cell monolayers. Three different conditions were studied to explore the effect of regionally slowed conduction on wave propagation and reentry: depolarization by elevated extracellular potassium, sodium channel inhibition with lidocaine, and cell-cell decoupling with palmitoleic acid. Using optical mapping of transmembrane voltage, we found that the central region of slowed conduction always served as the core region around which a spiral wave formed and then revolved following a period of rapid pacing. Because of the localized slowing in the core region, we observed experimentally for the first time an S shape of the spiral wave front near its tip. These results indicate that a small region of slowed conduction can play a crucial role in the formation, anchoring, and modulation of reentrant spiral waves.
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University, 720 Rutland Avenue, Baltimore, MD 21205, USA.
authors.forename: Joyce W
authors.initials: JW
authors.lastname: Lin
authors.forename: Libet
authors.initials: L
authors.lastname: Garber
authors.forename: Yue Rosa
authors.initials: YR
authors.lastname: Qi
authors.forename: Marvin G
authors.initials: MG
authors.lastname: Chang
authors.forename: Joshua
authors.initials: J
authors.lastname: Cysyk
authors.forename: Leslie
authors.initials: L
authors.lastname: Tung
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000831:Animals, Newborn; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001145:Arrhythmias, Cardiac / Q000378:metabolism* / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial; D018929:Cell Culture Techniques / Q000295:instrumentation*; D002478:Cells, Cultured; D004867:Equipment Design; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology; D006352:Heart Ventricles / Q000166:cytology / Q000378:metabolism; D008012:Lidocaine / Q000494:pharmacology; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors
chemical_list: D000889:Anti-Arrhythmia Agents; D005229:Fatty Acids, Monounsaturated; C008757:palmitoleic acid; D008012:Lidocaine; D011188:Potassium