Class IC antiarrhythmics are agents that decrease the maximal rate of depolarization while having no effect on the duration of the myocardial action potential. Agents in Class IC include flecainide and encainide . The structures of these agents are shown below. Class II Antiarrhythmics Class II antiarrhythmics are beta adrenergic blockers, which we have previously discussed. These agents block the role of adrenergic neurons in the generation of certain types of arrhythmias, and are also anesthetic at higher doses.
Beta blockers approved for their antiarrhythmic effects include propranolol and sotalol .
The structures of these agents are shown below. Class III Antiarrhythmics Class III antiarrhythmics are agents that cause homogeneous prolongation of the duration of the myocardial action potential, and include bretylium tosylate and amiodarone . The structures of these agents are shown below. Class IV Antiarrhythmics Class IV antiarrhythmics are all calcium channel blockers, which we have previously discussed. They block the slow inward current that is carried by calcium ions during the myocardial action potential.