title: Contact fluorescence imaging of reentry in monolayers of cultured neonatal rat ventricular myocytes.
abstract: BACKGROUND
  We present a novel contact fluorescence imaging (CFI) approach to monitor transmembrane potentials in monolayers of cultured neonatal rat ventricular cells. We apply CFI to demonstrate, for the first time, long-term recordings as well as electrical induction and termination of reentrant activity in this in vitro model.
  
  
  RESULTS
  CFI was performed in confluent cell monolayers stained with di-8-ANEPPS. An anatomic obstacle (6 x 0.5 mm) was created in the center of the monolayers. Reentry was induced with a premature stimulus after pacing at 2 Hz (both via field stimulation). Seven sustained (>3 min) reentrant episodes, anchored to the anatomic obstacle, were observed in three monolayers. Field stimulation (30 V/cm) was applied to successfully terminate 6 of the 7 reentries. Analysis of reentrant activity showed similarities with anatomic reentry in tissue preparations, such as reduced conduction velocity around the core, variable conduction velocity along the reentrant pathway due to wavefront curvature effects, and field-induced activation at the obstacle borders leading to reentry termination (cardioversion).
  
  
  CONCLUSIONS
  This study demonstrates the feasibility of CFI for macroscopic optical mapping of transmembrane potentials in a single layer of cultured cells. Our results suggest that the monolayer cell culture model is an attractive complement to tissue models of reentry and cardioversion.
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: E
authors.initials: E
authors.lastname: Entcheva
authors.forename: S N
authors.initials: SN
authors.lastname: Lu
authors.forename: R H
authors.initials: RH
authors.lastname: Troppman
authors.forename: V
authors.initials: V
authors.lastname: Sharma
authors.forename: L
authors.initials: L
authors.lastname: Tung
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D002478:Cells, Cultured; D003952:Diagnostic Imaging; D005240:Feasibility Studies; D005453:Fluorescence; D005456:Fluorescent Dyes; D008564:Membrane Potentials / Q000502:physiology; D009206:Myocardium / Q000473:pathology; D011726:Pyridinium Compounds; D051381:Rats; D017207:Rats, Sprague-Dawley; D016276:Ventricular Function
chemical_list: C089669:1-(3-sulfonatopropyl)-4-(beta-(2-(di-n-octylamino)-6-naphthyl)vinyl)pyridinium betaine; D005456:Fluorescent Dyes; D011726:Pyridinium Compounds