Key result
Short-term amiodarone treatment primarily inhibits IKr (IC50=2.8 micromol/L), whereas long-term treatment reduces IKs to 55% of control.
Why the study?
Does amiodarone differentially affect the components of cardiac delayed rectifier K+ current depending on the duration of administration in rabbit ventricular myocytes and Xenopus oocytes?
Population
Ventricular myocytes isolated from rabbit hearts and Xenopus oocytes expressing cloned human channels
Comparison
Amiodarone vs Control rabbits/cells not exposed to amiodarone
Design
Preclinical
Follow-up
4 weeks (for long-term administration)
Authors
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Amiodarone duration effects on K+ currents should not change practice; leaves open differential impact in patients.
Does amiodarone differentially affect the components of cardiac delayed rectifier K+ current depending on the duration of administration in rabbit ventricular myocytes and Xenopus oocytes?
Amiodarone exhibits time-dependent differential effects on cardiac potassium channels, primarily inhibiting IKr acutely but reducing IKs with chronic administration.
Kamiya et al. (2001) studied Life-threatening tachyarrhythmias (experimental model). Amiodarone vs. Control was evaluated on Delayed rectifier K+ current (IK) components (IKr and IKs). Short-term amiodarone treatment primarily inhibits IKr (IC50=2.8 micromol/L), whereas long-term treatment reduces IKs to 55% of control.
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