Emergency treatment with nifekalant, a novel class III anti-arrhythmic agent, for life-threatening refractory ventricular tachyarrhythmias: post-marketing special investigation.
BACKGROUND
Because class I anti-arrhythmic drugs sometimes suppress cardiac function caused by their negative inotropic effects, they are not adequate for use in patients with severe heart failure, even as emergency treatment for life-threatening ventricular tachyarrhythmias (ventricular tachycardia (VT)/ventricular fibrillation (VF)).


RESULTS
An objective evaluation committee re-evaluated the effect of nifekalant in 191 patients with refractory VT/VF. The attack termination was achieved in 45 out of 93 patients (48.4%). Nifekalant was administered to 39 patients with direct-current (DC) shock-resistant VT/VF and directly terminated VT/VF in 9 patients. In 15 of the remaining 29 patients (51.7%), VT/VF was successfully cardioverted by additional DC shock after nifekalant administration. Prevention of recurrence was achieved in 60 out of 99 patients (60.6%). Corrected QT interval (QTc) was significantly prolonged after initial administration of nifekalant (0.463+/-0.056 to 0.504 +/-0.072), and during maintenance infusion (0.470 +/-0.056 to 0.547+/-0.070). As an adverse reaction, excess prolongation of QTc was noted in 11 patients including 3 patients with torsades de pointes. Hemodynamic parameters tended to improve after maintenance infusion of nifekalant.


CONCLUSIONS
Nifekalant is effective and useful for life-threatening refractory ventricular tachyarrhythmias, although careful observation of the QT interval is required.
Katoh
Takao
T
The First Department of Internal Medicine, Nippon Medical School, Japan. tkkt@nms.ac.jp
Mitamura
Hideo
H
Matsuda
Naoki
N
Takano
Teruo
T
Ogawa
Satoshi
S
Kasanuki
Hiroshi
H
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage*; D004632:Emergency Medical Services / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D040541:Marketing; D008875:Middle Aged; D011744:Pyrimidinones / Q000008:administration & dosage*; D016171:Torsades de Pointes / Q000188:drug therapy*; D014693:Ventricular Fibrillation / Q000188:drug therapy*
D000889:Anti-Arrhythmia Agents; D011744:Pyrimidinones; C076259:nifekalant