Clinical role of antiarrhythmic drugs in the prevention of Sudden Death

The role of antiarrhythmic drugs for prevention of sudden cardiac death has changed dramatically in the past 20 years. Though antiarrhythmics were once considered first-line therapy for the prevention of sudden death, clinical trials that demonstrated the proarrhythmia effects of Class I antiarrhythmics and others that established the superiority of implantable cardioverter defibrillator (ICD) implantation over amiodarone have driven ICD therapy to supplant antiarrhythmics as the standard of care in patients at high risk for sudden death. Based on current evidence, there is no role for Class I antiarrhythmics as the primary therapy for prevention of sudden death, and most Class III antiarrhythmics, including amiodarone, do not improve survival. Yet antiarrhythmic drugs remain frequently used. They may be clinically important in specific subsets of patients, such as in those with only moderate reductions in LV function, Brugada Syndrome, LQT Syndrome, or catecholaminergic polymorphic VT. Moreover, due to the negative impact of ICD shocks on quality of life, antiarrhythmics have become an important and widely used adjunctive therapy in patients with ICDs. Amiodarone, d,l-sotalol, and azimilide may help reduce both appropriate and inappropriate ICD therapies, and β-blockers and antiarrhythmics are used to treat electrical storm. Concerns that some antiarrhythmics may increase defibrillation threshold (DFT) and render ICD therapy ineffective may be allayed in light of advancements in ICD technology. Nevertheless, further investigation into this and other potential adverse interactions between antiarrhythmics and ICDs is needed.