[Treatment for perioperative arrhythmias with nifekalant hydrochloride]

Ventricular tachycardia (VT), ventricular fibrillation (VF), and atrial flutter (AFL) are potentially fatal or serious complications arising after cardiac surgery. Generally, we treat these complications with class I antiarrhythmic agents and/or direct counter shock (DC). However, sometimes these complications do not respond to antiarrhythmic agents and require frequent DC. Moreover, these class I agents induce heart failure due to their negative inotropic effect. Nifekalant hydrochloride (NIF) is a class III antiarrhythmic agent that prolongs the refractory period of the atrial and ventricular myocardium without any negative inotropic action. From July 2003 to September 2004, we treated 11 patients with NIF for perioperative arrhythmias (VT 5, VF 2, and AFL 4). NIF was administered by continuous intravenous infusion (0.3 to 0.4 mg/ kg/h) to prevent the recurrence of VT/VF and AFL. NIF prevented the recurrence of VT in 3 of the 5 cases. No recurrence was observed in 2 cases with VF. Furthermore, NIF prevented the recurrence of AFL in all the 4 patients. None of the patients exhibited changes in heart rate, cardiac output, and QTc interval. Additionally, no occurrence of Torsades de pointes was observed in any of the cases. In conclusion, NIF is an effective and safe antiarrhythmic agent for the treatment of perioperative arrhythmias under continuous monitoring of the QTc interval.