Antidysrhythmic agents at the turn of the twenty-first century: a current review

The use of class IA agents is gradually on the decline, primarily as a result of its unfavorable risk-to-benefit ratio. Lidocaine, a class IB agent, has been widely used in the acute treatment of VT. However, alternate drugs are being considered increasingly as first-line agents in the acute treatment of VT. Class IC drugs are contraindicated in patients with structural cardiac abnormalities and have a limited usefulness in the management of dysrhythmias. Beta-blockers continue to increase their role in cardiology, and subsequently their use in managing dysrhythmias. Class III agents, including amiodarone, sotalol, ibutilide, and dofetilide, are among the most widely used antidysrhythmics. Class IV calcium channel blockers have a limited usefulness in tachydysrhythmias. Digoxin and adenosine have unique antidysrhythmic properties and will likely retain their roles as antidysrhythmic agents. In the wake of the effectiveness of amiodarone, the drug that crosses all classes, some now question the benefit of pure agents that block a single, specific ion channel in the heart. After CAST8 demonstrated that antidysrhythmics can increase mortality while seemingly suppressing dysrhythmias, new drugs will continue to undergo intense scrutiny with regard to their efficacy, safety, and usefulness in treating dysrhythmias.