Nifekalant versus lidocaine for in-hospital shock-resistant ventricular fibrillation or tachycardia

ObjectiveTo compare the efficacy and safety of nifekalant, a pure class III anti-arrhythmic drug, and lidocaine in patients with shock-resistant in-hospital ventricular fibrillation (VF) or ventricular tachycardia (VT).Patients and methodsBetween August 2005 and March 2008, we conducted a prospective, two-arm, cluster observational study, in which participating hospitals were pre-registered either to the nifekalant arm or the lidocaine arm. Patients were enrolled if they had in-hospital VF or VT resistant to at least two defibrillation shocks. Congenital or drug-induced long QT syndrome was excluded. The primary end-point was termination of VF or VT with/without additional shock. The secondary end-points were return of spontaneous circulation (ROSC), 1-month survival and survival to hospital discharge. We also assessed the frequency of adverse events, including asystole, pulseless electrical activity and torsade de pointes.ResultsIn total, 55 patients were enrolled. After nifekalant, 22 of 27 patients showed termination of VF or VT, as compared with 15 of 28 patients treated with lidocaine with/without additional shock (odds ratio (OR): 3.8; 95% confidence interval (CI): 1.1–13.0; P = 0.03). Twenty-three of 27 patients given nifekalant showed ROSC, as compared with 15 of 28 patients given lidocaine (OR: 5.0; 95% CI: 1.4–18.2; P = 0.01). There was no difference in 1-month survival or survival to hospital discharge between the nifekalant and lidocaine arms. There was a higher incidence of asystole with lidocaine (7 of 28 patients) than with nifekalant (0 of 27 patients) (P = 0.005). Torsade de pointes was not observed.ConclusionNifekalant was more effective than lidocaine for termination of arrhythmia and for ROSC in patients with shock-resistant in-hospital VF or VT (umin-CTR No. UMIN 000001781).