Intravenous antiarrhythmic drug therapy in the resuscitation from refractory ventricular arrhythmias.

Prompt cardiopulmonary resuscitation (CPR) and early defibrillation significantly improve the likelihood of successful resuscitation from cardiac arrest and are the key components in the American Heart Association's "chain of survival." Although representing current clinical practice in the United States, there is limited evidence supporting the benefit of acute administration of such antiarrhythmic medications as lidocaine, bretylium, magnesium, and procainamide to a victim of cardiac arrest. There has been only 1 published case-controlled clinical trial in which shock-refractory victims of out-of-hospital ventricular fibrillation were stratified into those who received lidocaine and those who did not. In this trial, no significant differences were observed between treatment groups in the return of an organized rhythm, admission to the hospital, or survival to hospital discharge. In the recently published ARREST trial, a significant improvement in admission alive to the hospital was observed in recipients of intravenous amiodarone, compared with placebo (44% vs 34%, respectively, p = 0.03). With the possible exception of intravenous amiodarone, available evidence of definitive benefit from antiarrhythmic drugs in cardiac arrest is inconclusive. Due to regulatory issues, clinical trials in cardiac arrest are extremely difficult to design and perform.