Antiarrhythmic drugs for cardiac arrest with a shockable rhythm and their effect on outcomes – A systematic review with meta-analysis

Background Antiarrhythmic drugs are used during cardiopulmonary resuscitation (CPR) to improve the chances of return of spontaneous circulation (ROSC) in shockable rhythms. To date, their impact on clinical outcomes remains uncertain. This review aimed to provide an evaluation of respective up-to-date evidence. Methods We searched Embase, MEDLINE(R), and Cochrane Central Register of Controlled Trials. Data on study design, population characteristics, antiarrhythmic drugs used, and predefined outcomes were extracted. A meta-analysis was conducted in groups with at least three studies reporting the same outcome. Additionally, we performed subgroup analysis according to the study design. Results Initially, 5,080 studies were identified, and 29 were included, with, in total, 60,205 patients. A statistically significant difference in achieving ROSC was found comparing 1) lidocaine and no lidocaine, favouring lidocaine (OR = 1.61, 95% CI: 1.11 - 2.32, p=0.01), 2) nifekalant and lidocaine, favouring nifekalant (OR = 4.18, 95% CI: 2.23 - 7.83, p<0.00001), and 3) esmolol and no esmolol, favouring esmolol (OR = 3.0, 95% CI: 1.40 - 6.40, p=0.005). For the effect on survival to hospital discharge, a significant difference between lidocaine and no lidocaine, favouring lidocaine (OR = 1.66, 95% CI: 1.02 - 2.7, p=0.04), was found. Conclusion Evidence supporting the use of any antiarrhythmic drugs during CPR remains limited and is partly inconclusive. For the effect on survival to hospital discharge, a statistically significant difference was only found favouring the administration of lidocaine compared to no lidocaine. Further research with improved trial design and into novel drug options should be conducted.