Blockade of cardiac outwardly rectifying K+ channels by TEA and class III antiarrhythmics ? evidence against a single drug-sensitive channel site

1994 ◽  
Vol 22 (6) ◽  
Author(s):  
I. Benz ◽  
M. Kohlhardt
Keyword(s):  
Class Iii ◽  
K Channels ◽  
Single Drug ◽  
Class Iii Antiarrhythmics

scholarly journals Class III Antiarrhythmics: put to the SWORD?

Heart ◽  
1996 ◽  
Vol 75 (2) ◽  
pp. 111-113 ◽  
Author(s):  
S. M. Cobbe
Keyword(s):  
Class Iii ◽  
Class Iii Antiarrhythmics

Mechanisms Underlying the QT Interval–prolonging Effects of Sevoflurane and Its Interactions with Other QT-prolonging Drugs

2006 ◽  
Vol 104 (5) ◽  
pp. 1015-1022 ◽  
Author(s):  
Jiesheng Kang ◽  
William P. Reynolds ◽  
Xiao-Liang Chen ◽  
Junzhi Ji ◽  
Hongge Wang ◽  
...  
Keyword(s):  
Action Potential ◽  
Action Potential Duration ◽  
Antiarrhythmic Drugs ◽  
Ventricular Repolarization ◽  
K Channel ◽  
Na Channel ◽  
Ca Channel ◽  
Class Iii ◽  
K Channels ◽  
Channel Currents

Background Sevoflurane prolongs ventricular repolarization in patients, but the mechanisms are not fully characterized. The effects of sevoflurane on many cloned human cardiac ion channels have not been studied, and the interactions between sevoflurane and other drugs that prolong cardiac repolarization have not been detailed. Methods The effects of sevoflurane on action potentials and L-type Ca channels in guinea pig myocytes were examined. Sevoflurane's effects on cloned human cardiac K channels and the cloned human cardiac Na channel were studied. The consequences of combining sevoflurane and the class III antiarrhythmic drugs sotalol or dofetilide on action potential duration were also examined. Results Sevoflurane produced an increase in action potential duration at concentrations of 0.3-1 mm. Contrary to most drugs that delay ventricular repolarization, sevoflurane was without effect on the human ether-a-go-go-related gene cardiac potassium channel but instead produced a reduction in KvLQT1/minK K channel currents and inhibited the Kv4.3 K channel by speeding its apparent rate of inactivation. Sevoflurane had little effect on Na and Ca channel currents at concentrations of 1 mm or less. When the authors coadministered sevoflurane with sotalol or dofetilide, synergistic effects on repolarization were observed, resulting in large increases in action potential duration (up to 66%). Conclusion Prolonged ventricular repolarization observed with administration of sevoflurane results from inhibition of KvLQT1/minK and Kv4.3 cardiac K channels. Combining sevoflurane with class III antiarrhythmic drugs results in supra-additive effects on action potential duration. The results indicate that sevoflurane, when administered with this class of drug, could result in excessive delays in ventricular repolarization. The results suggest the need for further clinical studies.

scholarly journals Effects of class III antiarrhythmic drugs on the Na+-activated K+ channels in guinea-pig ventricular cells

1996 ◽  
Vol 119 (1) ◽  
pp. 133-141 ◽  
Author(s):  
Katsumi Mori ◽  
Toshihiro Saito ◽  
Yoshiaki Masuda ◽  
Haruaki Nakaya
Keyword(s):  
Guinea Pig ◽  
Antiarrhythmic Drugs ◽  
Class Iii ◽  
K Channels ◽  
Ventricular Cells
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