PMID: 8985806Dec 1, 1996Paper

Flecainide and the electrophysiologic matrix: the effects of flecainide acetate on the determinants of cardiac excitability in sheep Purkinje fibers

Journal of Cardiovascular Electrophysiology
M F Arnsdorf, G J Sawicki

Abstract

Flecainide was associated with excess mortality distributed virtually equally throughout the period of the Cardiac Arrhythmia Suppression Trial, suggesting the intersection of two events, drug effect and perhaps ischemia. Flecainide's effect on active properties has been studied extensively, but nothing is known of its effects on passive properties or on the balance among active and passive cellular properties that determines cardiac excitability. The multiple microelectrode method of intracellular current application and transmembrane voltage recording was used in sheep Purkinje fibers to determines strength- and charge-duration as well as constant current-voltage relationships and to estimate active properties, liminal length, and cable properties at a normal [K+]o and in a setting of hyperkalemia analogous to that of ischemia. A computer tracked in time the alterations in the active and passive properties relevant to excitability. Flecainide slightly decreased excitability at a normal [K+]o, primarily by depressing the sodium system with some contributory effect of passive properties. At high [K+]o, flecainide caused a frequency-dependent decrease in excitability and conduction, the latter best interpreted as a failure of th...Continue Reading

References

May 1, 1977·Progress in Cardiovascular Diseases·M F Arnsdorf
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Citations

Nov 30, 2000·Archives of Physiology and Biochemistry·B P HoekstraJ DeGoede
Jul 18, 2020·American Journal of Physiology. Heart and Circulatory Physiology·Gregory S HoekerSteven Poelzing

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