Amiodarone and lidocaine are associated with slightly better survival outcomes compared with placebo in patients with non-shockable-turned-shockable out-of-hospital cardiac arrest (OHCA), according to a randomized double-blind study published in Circulation.
Investigators randomly assigned adult patients with non-traumatic OHCA and shock-refractory ventricular fibrillation/pulseless ventricular tachycardia (VF/VT) to either amiodarone, lidocaine, or placebo. The primary outcome of this study was survival to hospital discharge, and secondary outcomes included adverse drug-related events and functional status at discharge. A total of 1063 patients with initial non-shockable-turned-shockable rhythms and 3026 patients with initial VF/VT were included in the final analysis.
Patients who received either amiodarone or lidocaine required fewer drug doses, fewer ancillary antiarrhythmic drugs, and fewer shocks than those who received placebo (P <.05). There was no significant difference among the 3 groups with regard to survival to hospital discharge (P =.24).
In addition, no significant interaction was observed concerning assigned treatment and discharge survival with initiating OHCA rhythms, which included pulseless electrical activity, asystole, or VF/VT. Following adjustment of absolute differences, survival was found to be 2.3% for amiodarone (95% CI, –0.3 to 4.8; P =.08) vs placebo and 1.2% for lidocaine vs placebo 1.2% (95% CI, –1.1 to 3.6; P =.30).
Because high-risk patients with an expected poor prognosis were included, the study was inherently underpowered to provide significant insight into clinically relevant treatment effects. The study also failed to demonstrate direct efficacy comparisons of lidocaine and amiodarone.
The researchers noted, however, “[T]he consistent trends toward improved survival could also be interpreted as potential signals of benefit from active-drug treatment.”
In addition, if the drugs were proven effective, “improving absolute survival by merely 2% in this patient population means more than 1000 additional lives might be saved each year in North America from non-shockable-turned-shockable OHCA alone.”
Kudenchuk PJ, Leroux BG, Daya M, et al. Antiarrhythmic drugs for non-shockable-turned-shockable out-of-hospital cardiac arrest: the Amiodarone, Lidocaine or Placebo Study (ALPS) [published online September 13, 2017]. Circulation doi:10.1161/CIRCULATIONAHA.117.028624