The effects of nifekalant hydrochloride on the QT dispersion after direct-current defibrillation.
BACKGROUND
Although nifekalant hydrochloride (NIFE) has been demonstrated to suppress ventricular tachyarrhythmia, especially electrical storm, the mechanism by which it does so is still unclear. We examined its effects on the spatial dispersion of repolarization (SDR) after implantable cardioverter-defibrillator (ICD) shock.


RESULTS
In twenty five patients with an ICD, we recorded the 87-lead ECG during sinus rhythm (the CONTROL group) under general anesthesia, after NIFE administration alone, and just after termination of induced ventricular fibrillation (VF) by ICD shock with or without NIFE administration. In all recordings, the corrected QT interval (QTc) was measured in each lead. The dispersion of QTc (QTc-D; maximum QTc minus minimum QTc) was also measured. Compared with the CONTROL, the QTc-D exhibited significant deterioration after ICD shock (61 +/- 12, 91 +/- 24 ms(1/2), respectively, p < 0.001). However, the QTc-D after NIFE administration either with or without ICD shock did not differ from the CONTROL group (65 +/- 20, 61 +/- 18, and 61 +/- 12 ms(1/2), respectively, p = 0.99).


CONCLUSIONS
NIFE suppressed the deterioration of SDR by ICD shock. This might be a mechanism by which NIFE suppresses recurrence of ventricular tachyarrhythmia after ICD shock.
Maeda
Keiko
K
Department of Internal Medicine and Cardiology, Osaka City University, Graduate School of Medicine, Japan.
Takagi
Masahiko
M
Tatsumi
Hiroaki
H
Nakagawa
Eiichiro
E
Yoshiyama
Minoru
M
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000368:Aged; D000638:Amiodarone / Q000494:pharmacology; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D017147:Defibrillators, Implantable; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011744:Pyrimidinones / Q000494:pharmacology*; D013015:Sotalol / Q000494:pharmacology; D017180:Tachycardia, Ventricular / Q000503:physiopathology / Q000628:therapy; D014693:Ventricular Fibrillation / Q000503:physiopathology / Q000628:therapy; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology
D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D011744:Pyrimidinones; C076259:nifekalant; D013015:Sotalol; D000638:Amiodarone