Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Stark, G; Dhein, S; Bachernegg, M; Ziskoven, U; Zhao, Y; Klaus, W; Kickenweiz, E; Decrinis, M; Tritthart, HA.
Frequency-dependent effects of propafenone decrease with duration of ventricular tachycardia in isolated guinea pig hearts.
Eur J Pharmacol. 1994; 252(3):283-289
Doi: 10.1016/0014-2999(94)90174-0
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- Co-Autor*innen der Med Uni Graz
- Tritthart Helmut
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- Abstract:
- Na+ channel blockers terminate tachyarrhythmias primarily by rate-dependent effects. The purpose of this study was to investigate the use-dependent effects of propafenone in isolated guinea pig and rabbit hearts perfused by the method of Langendorff. In the presence of propafenone (0.3 microM) during ventricular pacing, an abrupt decrease of the pacing cycle length (220 ms to 120 ms) slowed the intraventricular conduction with a transient peak QRS prolongation of 33.8 +/- 2.0% after 5.7 +/- 0.5 s (P < 0.01) which subsequently decreased to a steady state of 14.0 +/- 2.5% after 38.0 +/- 5.5 s (mean +/- S.E.M.; n = 10; P < 0.01). The ventricular effective refractory period was significantly prolonged if evaluated by a train of 10 basic stimuli (S1) (interstimulus interval: 120 ms) followed by a premature stimulus (S2). However, when the train of basic stimuli was increased the effective refractory period diminished progressively. An initial increase in total activation time vanished with continued rapid ventricular stimulation. These effects may be explained by a shortening of the action potential during high rates resulting in a decreased binding of propafenone to Na+ channels.
- Find related publications in this database (using NLM MeSH Indexing)
- Action Potentials - drug effects
- Animals - drug effects
- Electrocardiography - drug effects
- Female - drug effects
- Guinea Pigs - drug effects
- Heart Conduction System - drug effects
- Male - drug effects
- Propafenone - pharmacology
- Rabbits - pharmacology
- Sodium Channel Blockers - pharmacology
- Tachycardia, Ventricular - physiopathology
- Find related publications in this database (Keywords)
- Propafenone
- Frequency Dependence
- QRS Duration
- Ventricular Mapping