TABLE 1.

Clinical studies of role of lidocaine in cardiac arrest.

	Design	End points	Results
Wagner et al. 2022 60	Retrospective cohort study, 14,630 patients were enrolled. Patients receiving amiodarone or lidocaine for VF/VT in‐hospital cardiac arrest refractory to CPR were analyzed.	Primary end point: ROSC, secondary outcomes: 24 h survival, survival to hospital discharge and favorable neurologic outcome	Compared with amiodarone, lidocaine was associated with significantly higher odds of ROSC (OR: 1.15), 24 h survival (OR: 1.16), survival to discharge (OR: 1.19)
Kudenchuk et al. 2016 43	Randomized, double‐blind trial, 3026 patients were enrolled. In patients with out‐of‐hospital cardiac arrest, shock‐refractory VF or pulseless VT after at least one shock, amiodarone, lidocaine, and placebo were compared.	Primary end point: Survival to hospital discharge. Secondary end point: Favorable neurologic function	Amiodarone had a survival rate compared to placebo by 3.2 percentage points. For lidocaine versus placebo, the difference survival rate was 2.6 percentage points. For amiodarone versus lidocaine, the difference survival rate was 0.7 percentage points. None of the differences were statistically significant. Neurologic outcome at discharge was similar in the three groups.
Yoshie et al. 2014 42	Retrospective cohort study, 42 patients were enrolled. Clinical data of patients receiving lidocaine for the treatment of VF/VT were analyzed.	Primary end point: Effectiveness in terminating refractory ventricular arrhythmias	LVEF was significantly higher in the effective group (51 ± 16% vs. 32 ± 9%). Regardless of the LVEF, combination of amiodarone and lidocaine was more effective than admission of lidocaine only.
Kudenchuck et al. 2013 61	Retrospective cohort study, 1721 patients were enrolled. Patients with witnessed out‐of‐hospital‐cardiac‐arrest and VT/VF who did or did not receive prophylactic lidocaine at first ROSC were analyzed.	Primary end point: Frequency of re‐arrest from recurrent VF/VT after initial ROSC, admission alive to hospital, survival to hospital discharge	Prophylactic lidocaine was associated with reduced odds of re‐arrest from VF/VT (OR: 0.34) and from nonshockable arrhythmias (0.47), a higher hospital admission rate (1.88) and improved survival to discharge (1.49).
Shiga et al. 2010 62	Prospective, observational study, 55 patients were enrolled. Patients with in‐hospital VF or VT resistant to at least two shocks were analyzed after participating hospitals were pre‐registered either to nifekalant or lidocaine.	Primary end point: Termination of VF or VT with/without additional shock. Secondary endpoints: ROSC, 1‐month survival, and survival to hospital discharge	Patients with nifekalant therapy showed significantly higher termination rates of VF or VT as compared with patients treated with lidocaine (OR: 3.8). There was no difference in 1‐month survival between the two groups. There was a higher incidence of asystole with lidocaine (7 of 28 patients) than with nifekalant (0 of 27 patients).
Rea et al. 2006 63	Multicenter retrospective study, 194 patients were enrolled. Hospitalized patients who received amiodarone, lidocaine, or a combination for pulseless VT/VF were analyzed.	Primary end point: Proportion of patients alive 24 h post‐cardiac arrest	Among the lidocaine group, the amiodarone‐group, and the combination‐group, there were no differences in the proportion of patients alive 24 hs post‐cardiac arrest (p = 0.39). The likelihood of survival in patients who received amiodarone was decreased as compared with lidocaine.
Dorian et al. 2002 64	Randomized, double‐blinded study, 347 patients were enrolled. Patients with out‐of‐hospital VF resistant to three shocks, i.v. epinephrine, and a further shock, or recurrent VF after initially successful defibrillation, were assigned to receive amiodarone + lidocaine placebo or i.v. lidocaine + amiodarone placebo.	Primary end point: Proportion of patients who survived to be admitted to the hospital	22.8% of the patients treated with amiodarone survived to hospital admission as compared with 12% of the patients treated with lidocaine (p = 0.009)
Herlitz et al. 1997 65	Retrospective cohort study, 1212 patients were enrolled. Patients with out‐of‐hospital‐cardiac arrest found in VF, with and without lidocaine treatment, were analyzed.	Primary end point: Survival to hospital discharge	In case of sustained VF, as well as after conversion to a pulse‐generating rhythm, patients treated with lidocaine had a higher rate of ROSC and were more likely to hospitalized alive (p < 0.01 for ROSC and being hospitalized alive). The proportion of patients being discharged did not significantly defer between the lidocaine and the no lidocaine groups.

Abbreviations: CPR, cardiopulmonary resuscitation; LVEF, left ventricular ejection fraction; OR, odds ratio; ROSC, return of spontaneous circulation; VF, ventricular fibrillation; VT, ventricular tachycardia.