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What is Which one of the following drugs is most likely to block K+ channels in the heart responsible for the delayed rectifier current? and explain in detail?
Amiodarone is a highly effective antiarrhythmic drug, in part because of its multiple actions, which include Na channel block, beta adrenoceptor block, K channel block, and Ca channel block. Drugs that block K channels (which include class IA and class III antiarrhythmics) prolong APD and ERP and predispose toward torsades de pointes ventricular arrhythmias. Encainide is a class IC drug, lidocaine and phenytoin are class IB, and verapamil is class IV, none of which inhibits the delayed rectifier K current responsible for membrane repolarization during the cardiac action potential.