title: Cesium chloride induced ventricular arrhythmias in dogs: three-dimensional activation patterns and their relation to the cesium dose applied.
abstract: BACKGROUND
  Cesium chloride has widely been used in experimental models to produce various ventricular arrhythmias. The study was designed to evaluate whether type and mechanism of these arrhythmias are dose-dependent.
  
  
  METHODS
  In 7 dogs with acute AV-block, 60 pins containing 4 bipolar electrodes each were inserted into both ventricles to provide 240 endo-, epi- and midmyocardial recording sites. A computerized mapping system was used to determine three-dimensional activation patterns of ventricular arrhythmias induced by three injections of 1 mmol/kg cesium chloride at 20 minute intervals.
  
  
  RESULTS
  Out of all arrhythmias induced, 25 ventricular extrasystoles, 31 monomorphic and 47 polymorphic ventricular tachycardias were mapped. Nonsustained ventricular tachycardias were readily inducible by a single bolus of cesium chloride, whereas sustained episodes required repetitive injections (1.45 +/- 0.61 vs. 2.61 +/- 0.57 doses, p < 0.05). Polymorphic tachycardias were observed more commonly than monomorphic tachycardias (87 vs. 31). Initiation and maintenance of cesium induced arrhythmias were exclusively based on focal mechanisms originating from the subendocardium, irrespective of morphology and dosage. All monomorphic arrhythmias were caused by repetitive firing of single immobile foci located in either the right or the left ventricle. Bi- and multifocal mechanisms, however, were found to underlie the polymorphic episodes.
  
  
  CONCLUSIONS
  Although there is a dose-dependence as to the sustenance of mono- or polymorphic tachycardias, this does not reflect on the three-dimensional activation pattern of cesium induced arrhythmias, which are due to mono- or multifocal activation originating from the subendocardium.
authors.affiliation: Medizinische Universitätsklinik, Abteilung Innere Medizin III, Heidelberg, Germany. Julia_Senges@med.uni-heidelberg.de
authors.forename: J C
authors.initials: JC
authors.lastname: Senges
authors.forename: L D
authors.initials: LD
authors.lastname: Sterns
authors.forename: K D
authors.initials: KD
authors.lastname: Freigang
authors.forename: A
authors.initials: A
authors.lastname: Bauer
authors.forename: R
authors.initials: R
authors.lastname: Becker
authors.forename: W
authors.initials: W
authors.lastname: Kübler
authors.forename: W
authors.initials: W
authors.lastname: Schoels
mesh_terms: D000818:Animals; D018780:Body Surface Potential Mapping; D002586:Cesium / Q000633:toxicity*; D002712:Chlorides / Q000633:toxicity*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000187:drug effects; D017180:Tachycardia, Ventricular / Q000139:chemically induced*
chemical_list: D002712:Chlorides; D002586:Cesium; C028019:cesium chloride