Antiarrhythmics in Cardiac Arrest: A Systematic Review and Meta-Analysis.

INTRODUCTION: It is widely accepted that antiarrhythmics play a role in cardiopulmonary resuscitation (CPR) universally, but the absolute benefit of antiarrhythmic use and the drug of choice in advanced life support remains controversial.

AIM: To perform a thorough, in-depth review and analysis of current literature to assess the efficacy of antiarrhythmics in advanced life support.

MATERIAL AND METHODS: Two authors systematically searched through multiple bibliographic databases including CINAHL, SCOPUS, PubMed, Web of Science, Medline(Ovid) and the Cochrane Clinical Trials Registry. To be included studies had to compare an antiarrhythmic to either a control group, placebo or another antiarrhythmic in adult cardiac arrests. These studies were independently screened for outcomes in cardiac arrest assessing the effect of antiarrhythmics on return of spontaneous circulation (ROSC), survival and neurological outcomes. Data was extracted independently, compared for homogeneity and level of evidence was evaluated using the Cochrane Collaboration's tool for assessing the risk of bias. The Mantel-Haenszel (M-H) random effects model was used and heterogeneity was assessed using the I2 statistic.

RESULTS AND DISCUSSION: The search of the literature yielded 30 studies, including 39,914 patients. Eight antiarrhythmic agents were identified. Amiodarone and lidocaine, the two most commonly used agents, showed no significant effect on any outcome either against placebo or each other. Small low quality studies showed benefits in isolated outcomes with esmolol and bretylium against placebo. The only significant benefit of one antiarrhythmic over another was demonstrated with nifekalant over lidocaine for survival to admission (p=0.003). On sensitivity analysis of a small number of high quality level one RCTs, both amiodarone and lidocaine had a significant increase in survival to admission, with no effect on survival to discharge.

CONCLUSIONS: This systematic review and meta-analysis suggests that, based on current literature and data, there has been no conclusive evidence that any antiarrhythmic agents improve rates of ROSC, survival to admission, survival to discharge or neurological outcomes. Given the side effects of some of these agents, we recommend further research into their utility in current cardiopulmonary resuscitation guidelines.