Do not consider amiodarone, give it! Comment on antiarrhythmic drugs for shock‑refractory ventricular fibrillation or pulseless ventricular tachycardia.

1 significant difference between the 3 study groups in the primary outcome at discharge from the hos‐ pital, or the secondary outcome of favourable neu‐ rologic status at discharge. The authors of the study concluded that “Over‐ all, neither amiodarone nor lidocaine resulted in a significantly higher rate of survival or favor‐ able neurologic outcome than the rate with pla‐ cebo among patients with out ‐of ‐hospital cardiac arrest due to initial shock ‐refractory ventricular fibrillation or pulseless ventricular tachycardia.”4 However, this statement may be misleading. Here the devil is, as usual, in the details. First, the overall lack of statistical significance brings an issue of clinical interpretation of that very concept. The 3.2% absolute difference in sur‐ vival to discharge between amiodarone and pla‐ cebo (and 2.6% between lidocaine and placebo) is nonsignificant (P values of 0.08 and 0.16, re‐ spectively). However, if this is a real difference, it is very likely of clinical importance. Similarly, a 2.2% absolute difference in favorable neurolog‐ ical outcome in favor of amiodarone versus place‐ bo (nonsignificant) was observed. In this sense, lack of proof of a significant difference should not be interpreted as proof of a lack of such differ‐ ence. Of note, looking at the absolute numbers, the improvement in survival rate was accompa‐ nied by a nonsignificant 1% absolute increase in survival of people with severe or very severe neu‐ rological disability. Second and more importantly, there was a dif‐ ference in survival among the predefined sub‐ group of those who suffered witnessed cardiac ar‐ rest (and, presumably, received faster interven‐ tion): the survival rate was higher with amioda‐ rone (27.7%) or lidocaine (27.8%) than with pla‐ cebo (22.7%). The absolute risk difference (this time statistically significant) is likely larger than, for example, any medication intervention used in the short to medium term in acute coronary syndrome, or for several years in hypertension or hyperlipidemia. This difference was yet larg‐ er if the arrest was witnessed by emergency ser‐ vices personnel: survival to discharge was 38.6% among amiodarone ‐treated patients versus 23.3% To the Editor Cardiac arrest is an event of such speed and intensity that predetermined man‐ agement guided by algorithms is likely needed to provide a meaningful chance of survival. Cur‐ rent European and North American guidelines call for immediate and effective cardiopulmonary re‐ suscitation (CPR) and rapid delivery of defibril‐ lation for shockable rhythms (ie, ventricular fi‐ brillation [VF], pulseless ventricular tachycardia [pVT]).1,2 Definitive airway management follows closely. The use of drugs in cardiac arrest, howev‐ er, remains controversial. Epinephrine remains recommended, while vasopressin has been removed from the guide‐ lines as single vasoactive therapy in cardiac ar‐ rest. The use of antiarrhythmic drugs (ie, amio‐ darone or lidocaine) for VF/pVT is recommend‐ ed in European guidelines, and North American guidelines suggest these medications be consid‐ ered under such circumstances when defibrilla‐ tion and epinephrine have not restored spontane‐ ous circulation.1,2 However, the evidence to sup‐ port these recommendations is of low to very‐ ‐low quality with an overall lack of information on long ‐term patient important outcomes.3 Re‐ cently, the results of a study by the Resuscitation Outcomes Consortium of amiodarone versus li‐ docaine versus placebo in patients with out ‐of‐ ‐hospital shock ‐refractory VF or pVT cardiac ar‐ rest have provided some new insights into this clinical question.4 In this study, adults with nontraumatic, shock‐ ‐refractory, out ‐of ‐hospital VF and pVT were ran‐ domized to receive amiodarone, lidocaine, or pla‐ cebo. By way of cointervention, approximately 25% to 30% of patients in each group received intravenous bicarbonate, and between 5% and 10% received procainamide before hospital ad‐ mission. Approximately 75% of patients admitted to the hospital were treated with targeted tem‐ perature management and approximately 55% of them had coronary angiography in the first 24 hours. In this study population, between 20% and 25% of all such patients were discharged from the hospital, with between 16.6% and 18.8% hav‐ ing favorable neurological outcome. There was no LETTER TO THE EDITOR