Anti-arrhythmics in out-of-hospital cardiac arrest: lessons from a randomized controlled trial

In a randomized double-blind trial, Kudenchuk et al. (1) assessed the effectiveness of amiodarone lidocaine or placebo for out-of-hospital cardiac arrest (OHCA) due to shock refractory ventricular fibrillation (VF) or pulseless ventricular tachycardia (PVT). The main objective was to compare the survival hospital discharge between amiodarone recipients versus placebo recipients. Secondary comparisons for survival outcome have been realized for the patients between the groups “lidocaine versus placebo” and between the groups “amiodarone versus lidocaine”. The secondary outcome was the favorable neurologic function at discharge. Study outcomes was assessed in two populations: an efficacy or “modified intention to treat” population and a safety or “intention to treat decision” population. From May 2012 to October 2015, the Resuscitation Outcomes Consortium (ROC), a North American multicenter network with an emphasis on prehospital trials, has treated 7,051 shock refractory VF or PVT. Of these, 3,026 have benefited from the modified intention to treat analyses. In the amiodarone group, 24.4% survived to hospital discharge versus 23.7% in the lidocaine group and 21% in the placebo group. Neither of the two anti-arrhythmic did better than placebo (respectively P=0.08 and P=0.16) and the main outcome did not differ between amiodarone and lidocaine (P=0.70). However the study suggests that the survival could be improved by amiodarone administration versus placebo, in the particular case of bystander witnessed OHCA (P=0.01).