Nifekalant hydrochloride (NIF) is a novel intravenous class-III antiarrhythmic agent with a pirimidinedione structure that purely blocks the Kchannel without inhibiting β-adrenergic receptors. The authors investigated the efficacy of NIF for refractory ventricular tachycardia/ fibrillation (VT/VF). They studied 30 patients treated with an intravenous infusion of NIF [ 26 men, 4 women; age: 63 ± 17 (mean ± SD) years] at a dose of 0.19 ± 0.14 mg/kg body weight per hour. Sixteen were patients with acute coronary syndrome (ACS), and 14 were patients with chronic structural heart disease (Chr-HD). Amiodarone and sotalol had already been administered to 9 patients with Chr-HD before the administration of NIF. The QT and T peak-end (Tp-e) intervals were measured and corrected by Bazett's method (QTc, cTp-e). The left ventricular ejection fraction was depressed (28 ± 9%). NIF was effective for preventing VT/VF without proarrhythmia and hemodynamic deterioration in 21 patients (70%; 12 with ACS; 9 with Chr-HD), but ineffective in 4 patients (all with Chr-HD). The QTc prolongation in the responders was more pronounced than in the nonresponders (25% ± 15% versus 5% ± 7% increase; P < 0.05). Proarrhythmic torsade de pointes (TdP) developed transiently in the remaining 5 patients in whom the cTp-e was markedly increased compared with that in the responders (93% ± 49% versus 37% ± 41% increase; P < 0.05). In conclusion, these findings indicate that the intravenous administration of NIF is useful in the emergent treatment of inhibiting drug-refractory VT/VF, although proarrhythmic TdP owing to an enhancement of transmural dispersion of repolarization needs to be taken into account.
|Number of pages||6|
|Journal||Journal of cardiovascular pharmacology|
|Publication status||Published - 2006 Dec|
- Antiarrhythmia agents
- Torsade de pointes
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine