title: Differential class III antiarrhythmic effects of ambasilide and dofetilide at different extracellular potassium and pacing frequencies.
abstract: We studied the effect of two new class II antiarrhythmics, ambasilide and dofetilide, on the action potential duration (APD) of guinea pig right ventricular papillary muscle at different extracellular potassium concentrations ([K+e]) and pacing frequencies. Under normal [K+e], both drugs significantly prolonged APD90 (APD at 90% repolarization) at 0.5 Hz. The effect of ambasilide was well preserved at rapid pacing rates, independent of [K+e]. The effect of dofetilide was markedly reduced with increasing pacing rate, especially in high [K+e]. Therefore, ambasilide may be useful in treating tachyarrhythmias in normal, as well as in altered [K+e] conditions.
authors.affiliation: Medizinische Klinik, Klinikum rechts der Isar, München, Germany.
authors.forename: V
authors.initials: V
authors.lastname: Gjini
authors.forename: M
authors.initials: M
authors.lastname: Korth
authors.forename: J
authors.initials: J
authors.lastname: Schreieck
authors.forename: S
authors.initials: S
authors.lastname: Weyerbrock
authors.forename: A
authors.initials: A
authors.lastname: Schömig
authors.forename: C
authors.initials: C
authors.lastname: Schmitt
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D062365:Aminobenzoates / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D002304:Cardiac Pacing, Artificial; D005110:Extracellular Space / Q000187:drug effects / Q000502:physiology; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D010627:Phenethylamines / Q000494:pharmacology*; D011188:Potassium / Q000502:physiology*; D013449:Sulfonamides / Q000494:pharmacology*
chemical_list: D062365:Aminobenzoates; D000889:Anti-Arrhythmia Agents; D019086:Bridged Bicyclo Compounds, Heterocyclic; D010627:Phenethylamines; D013449:Sulfonamides; C075113:ambasilide; C063533:dofetilide; D011188:Potassium