Is the combination therapy of IKr-channel blocker and left stellate ganglion block effective for intractable ventricular arrhythmia in a cardiopulmonary arrest patient?

Abstract

Background: We have previously reported that the defibrillation success rate of intravenous nifekalant hydrochloride (NIF), a pure IKr-channel (IKr: the rapid components of the delayed rectifier potassium current) blocker, was more than 75% for lidocaine-resistant ventricular tachycardia and fibrillation (VT/VF) in patients with out-of-hospital cardiopulmonary arrest (CPA). However, there was no effective treatment for the remaining 25% of patients in whom defibrillation was unsuccessful. We hypothesised that the combination therapy of NIF and left stellate ganglion block (LSGB) was useful for defibrillation in NIF-resistant VT/VF and investigated its efficacy in a retrospective study. Methods and results: We investigated sequentially 272 out-of-hospital CPA patients treated at Tokai University between April and December 2006. VT/VF occurred in 55 patients on arrival or during cardiopulmonary resuscitation (CPR). On the basis of our CPR algorithm, NIF was administered (0.15-0.3 mg/kg, i.v.) after the first direct-current cardioversion. NIF-resistant VT/VFs were observed in 15 out of 55 patients and LSGB was performed on 11 of these with administration of NIF. Sinus rhythm was restored in 7 patients following LSGB (64%) and complete recovery was achieved in 2 patients. In the non-LSGB group, however, all the patients died. Conclusions: The combination therapy of intravenous NIF and LSGB was useful for defibrillation in intractable VT/VF. It is a potential and innovative treatment strategy for IKr-channel blocker resistant VT/VF. (Cardiol J 2007; 14: 355-365