Use-dependent electrophysiologic effects of amiodarone in coronary artery disease and inducible ventricular tachycardia

Chiamvimonvat, Nipavan; Mitchell, L. Brent; Gillis, Anne M.; Wyse, D. George; Sheldon, Robert S.; Duff, Henry J.

doi:10.1016/0002-9149(92)90198-8

Cited by 2 publications

(1 citation statement)

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“…This depends on the nonhomogeneous K+-efflux and local catecholamine content [16]. Therefore, the class I and IV effects of amiodarone observed in this study are favorable for prolonging the revolution time and for decelerating the ongoing reentrant tachycardia, which may, hence, become tolerable hemodynamically [38]. The class IV effects of amiodarone, which were shown to be more potent than the class I effects in the present study, are sometimes expected to abolish the slow conduction leading to the termination of the reentrant tachycardia.…”

Section: Discussionmentioning

confidence: 76%

Acute effects of amiodarone on membrane properties, refractoriness, and conduction in guinea pig papillary muscles

et al. 1995

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Amiodarone has potent and complex antiarrhythmic effects associated with a rare incidence of proarrhythmia. For a comprehensive understanding of its antiarrhythmic mechanisms in the same preparations, amiodarone (50 microM) was employed as it would be in the clinical setting and applied to guinea pig papillary muscles impaled by microelectrodes, paced at different rates, and superfused with various concentrations of potassium ([K]e). Amiodarone exerted complex actions, as follows: (1) The maximum rate of rise (Vmax) of the fast action potential (i.e., [K]e = 5.4-9.0 mM) as well as that of the slow action potential (i.e., [K]e = 15.0 mM in the presence of 1.0 microM isoproterenol) was suppressed in a rate-dependent manner. (2) Amiodarone exhibited a rate- and [K]e-dependent increase in the ratio of effective refractory period vs action potential duration at 90% repolarization (ERP/APD90), disclosing post-repolarization refractoriness. (3) Amiodarone had no effect on passive cable factors, such as threshold current and tissue resistance, during propagation. These versatile electrophysiological effects of amiodarone may contribute to its unique antiarrhythmic effects, as well as the low incidence of proarrhythmia with this drug.

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Section: Discussionmentioning

confidence: 76%