Cesium chloride induced ventricular arrhythmias in dogs: three-dimensional activation patterns and their relation to the cesium dose applied |
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Authors: | Julia C Senges Laurence D Sterns Kirsten D Freigang Alexander Bauer Rüdiger Becker Wolfgang Kübler Wolfgang Schoels |
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Institution: | Medizinische Universit?,tsklinik, Abteilung Innere Medizin III, Bergheimer Str. 58, D-69115 Heidelberg, Germany, E-mail: Julia_Senges@med.uni-heidelberg.de, DE
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Abstract: | Introduction: 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.
Received: 6 August 1999, Returned for 1. revision: 8 October 1999, 1. Revision received: 27 October 1999, Returned for 2.
Revision: 24 November 1999, 2. Revision received: 9 December 1999, Accepted: 9 December 1999 |
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Keywords: | Experimental electrophysiology – ventricular tachycardia – three-dimensional mapping – cesium chloride – dose-dependency |
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