Effect of nifekalant on life‐threatening ventricular arrhythmias in patients with cardiopulmonary resuscitation or during the perioperative state

Background: Nifekalant is a unique class III anti‐arrhythmic agent with a strong effect on prolonging the myocardial refractoriness, but its clinical effect is still unclear. In this study, we evaluated the effect of nifekalant on life‐threatening ventricular arrhythmias and compared the clinical background between the effective and non‐effective patients in order to clarify the clinical factors which may have an influence on the efficacy of nifekalant. Methods: The study population consisted of 47 consecutive patients who underwent nifekalant administration for life‐threatening ventricular arrhythmias (VT/VF). Their clinical characteristics and ECG parameters were retrospectively compared between patients with and without an effective result with the nifekalant administration. Results: Nifekalant was effective for refractory VT/VF in 26/47 patients. There was no significant difference in the age, gender or left ventricular ejection fraction, but the incidence of ischemic heart disease was higher in the effective group (17/26) than non‐effective group (9/21, p = 0.004). The incidence of in‐hospital events was higher in the effective group than non‐effective group (20/26 vs 10/21, p = 0.037). A significant prolongation in the QTc interval was observed in all patients and the degree of QTc prolongation was greater in the effective group than in the non‐effective group (0.46 ± 0.04 vs 0.43 ± 0.02 sec1/2, p = 0.026). Conclusion: Nifekalant was effective in 55% of the patients for refractory VT/VF. It was considered that nifekalant was more effective for patients with ischemic heart disease, during the perioperative period or in those experiencing in‐hospital events. The prolongation of the QTc interval might also be useful as an index for the efficacy of nifekelant administration.