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Aoki H, Suzuki T, Matsui H, Yasukochi S, Saiki H, Senzaki H, Nakamura Y. Efficacy of a pure Ikr blockade with nifekalant in refractory neonatal congenital junctional ectopic tachycardia and careful attention to damaging the atrioventricular conduction during the radiofrequency catheter ablation in infancy. HeartRhythm Case Rep 2017. [PMID: 28649501 PMCID: PMC5469282 DOI: 10.1016/j.hrcr.2017.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
- Hisaaki Aoki
- Department of Pediatrics, Faculty of Medicine, Kinki University, Osaka, Japan
- Address reprint requests and correspondence: Dr Hisaaki Aoki, Department of Pediatric Cardiology, Osaka Medical Center and Research Institute for Child and Maternal Health, 840 Murodocho Izumi, Osaka 594–1101, Japan.Department of Pediatric CardiologyOsaka Medical Center and Research Institute for Child and Maternal Health840 Murodocho IzumiOsaka594–1101Japan
| | - Tsugutoshi Suzuki
- Department of Pediatric Electrophysiology, Osaka City General Hospital, Osaka, Japan
| | - Hikoro Matsui
- Division of Pediatric Cardiology, Nagano Children's Hospital, Nagano, Japan
| | - Satoshi Yasukochi
- Division of Pediatric Cardiology, Nagano Children's Hospital, Nagano, Japan
| | - Hirofumi Saiki
- Department of Pediatric Cardiology, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Hideaki Senzaki
- Department of Pediatric Cardiology, Saitama Medical Center, Saitama Medical University, Saitama, Japan
| | - Yoshihide Nakamura
- Department of Pediatrics, Faculty of Medicine, Kinki University, Osaka, Japan
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Ando J, Kakishita M, Sakai K, Komura Y, Nishiyama K, Iwabuchi M, Yokoi H, Yasumoto H, Nosaka H, Nobuyoshi M. Efficacy of nifekalant hydrochloride in the treatment of fatal ventricular arrhythmia in patients with ischemic heart disease. Int Heart J 2006; 46:647-56. [PMID: 16157956 DOI: 10.1536/ihj.46.647] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Ventricular tachycardia (VT), which causes hemodynamic instability, and ventricular fibrillation (VF) sometimes occur in patients with severe underlying cardiovascular disease such as myocardial ischemia or infarction, and are associated with high mortality. This report presents the efficacy of nifekalant hydrochloride (nifekalant), a pure class III antiarrhythmic agent, in treating life-threatening ventricular arrhythmia in such patients. From June 2000, when nifekalant became commercially available in Japan, to May 2003, 30 ischemic heart disease (IHD) patients with VT/VF resistant to direct-current (DC) countershock received nifekalant in our hospital. These 30 patients served as the nifekalant group in this study. As a control group, we also included 33 IHD patients with VT/VF that had been resistant to DC countershock upon or during hospitalization between January 1996 and May 2000 before nifekalant became commercially available. No significant differences were observed in patient background factors and treatments between the two groups. The rates of death within 48 hours of occurrence of VT/VF were significantly lower in the nifekalant group (7%, 2/30) than in the control group (27%, 9/33; P < 0.03). The rates of cardiac death during hospitalization were also significantly lower in the nifekalant group (40%, 12/30) than in the control group (67%, 22/33; P < 0.03). The rates of survival until hospital discharge were significantly higher in the nifekalant group (57%, 17/30) than in the control group (30%, 10/33; P < 0.03). Multivariate analysis of all 63 patients revealed nifekalant administration was the factor that significantly improved the mortality (odds ratio for cardiac death, 0.26; 95% confidence interval (CI), 0.07 to 0.95; P = 0.041). Nifekalant improves the prognosis for life-threatening ventricular arrhythmia in IHD patients.
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Affiliation(s)
- Jiro Ando
- Department of Cardiology, Kokura Memorial Hospital, Kitakyushu, Fukuoka 802-8555, Japan
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Minami T, Isomoto S, Nakao K, Komiya N, Fukae S, Centurion OA, Yano K. Effects of intravenous nifekalant, a class III antiarrhythmic drug, on atrial vulnerability parameters in patients with paroxysmal atrial fibrillation. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2004; 27:212-7. [PMID: 14764172 DOI: 10.1111/j.1540-8159.2004.00412.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nifekalant, a class III antiarrhythmic drug, has been shown to suppress ventricular tachyarrhythmias, but its effects on AF are unclear. The aim of this study was to clarify the effects of nifekalant on the atrial vulnerability parameters in patients with paroxysmal AF. The study included 18 patients with paroxysmal AF who underwent electrophysiological study before and after intravenous infusion of nifekalant. The atrial electrophysiological parameters including the atrial effective refractory period (AERP), maximum intraatrial conduction delay, and wavelength index, calculated as the ratio of AERP to the maximum conduction delay, were quantitatively measured at baseline and during nifekalant infusion. The mean AERP was significantly prolonged from 214 +/- 27 ms at baseline to 242 +/- 39 ms after nifekalant (P < 0.001). Although earlier studies have shown that nifekalant does not affect the atrial conduction time, the mean maximum conduction delay of the study patients was significantly prolonged from 59 +/- 19 ms at baseline to 72 +/- 28 ms after nifekalant (P = 0.015). There was no significant difference in the wavelength index at baseline (4.1 +/- 1.7) and after nifekalant (4.1 +/- 2.5). However, when the differences of AERP and wavelength index were defined as each parameter during nifekalant infusion minus that at baseline, the difference of AERP showed a direct positive correlation with that of the wavelength index (P = 0.013). In conclusion, nifekalant may be effective in the prevention of AF due to prolongation of the AERP. However, in those patients who have a lesser degree of prolongation of the AERP by nifekalant, the wavelength index tended to be decreased, suggesting that the drug might augment the propensity for AF.
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Affiliation(s)
- Takako Minami
- Division of Cardiovascular Medicine, Department of Translational Medical Sciences, Course of Medical and Dental Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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Satoh Y, Sugiyama A, Takahara A, Chiba K, Hashimoto K. Electropharmacological and Proarrhythmic Effects of a Class III Antiarrhythmic Drug Nifekalant Hydrochloride Assessed Using the In Vivo Canine Models. J Cardiovasc Pharmacol 2004; 43:715-23. [PMID: 15071360 DOI: 10.1097/00005344-200405000-00015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cardiovascular effects of Nifekalant were examined using halothane-anesthetized dogs, and its proarrhythmic potential was estimated with chronic complete atrioventricular block dogs. Nifekalant was intravenously administered to the halothane-anesthetized dogs in three doses of 0.03, 0.3, and 3 mg/kg/10 minutes with a pause of 20 minutes (n = 6). The low dose hardly affected any of the cardiovascular parameters. The middle dose, a clinically recommended antiarrhythmic dose, decreased the total peripheral resistance, increased the cardiac output, and prolonged the ventricular repolarization phase and effective refractory period. The high dose increased the left ventricular contraction, transiently decreased the mean blood pressure, and enhanced the atrioventricular conduction, besides potentiation of the changes induced by the middle dose. Increment in the repolarization phase by the high dose was greater than that in the refractoriness, leading to increase of ventricular electrical vulnerability. To the atrioventricular block animals, clinically relevant antiarrhythmic dose of 3 mg/kg p.o. of Nifekalant and its 10-times-higher dose were administered. The high dose prolonged QT interval leading to torsades de pointes in all animals (n = 5), which was not detected by the clinical dose (n = 5). These results suggest that antiarrhythmic dose of Nifekalant can be used safely; however, caution should be paid for patients complicating bradycardia and/or a risk of elevated plasma drug concentration.
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Affiliation(s)
- Yoshioki Satoh
- Department of Medicine, Koshu Rehabilitation Hospital, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan
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Yoshida H, Sugiyama A, Satoh Y, Ishida Y, Yoneyama M, Kugiyama K, Hashimoto K. Comparison of the in vivo electrophysiological and proarrhythmic effects of amiodarone with those of a selective class III drug, sematilide, using a canine chronic atrioventricular block model. Circ J 2002; 66:758-62. [PMID: 12197602 DOI: 10.1253/circj.66.758] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Amiodarone effectively blocks both the sodium and calcium channels and beta-adrenoceptors, in addition to blocking several potassium currents including IKr, IKs, Ito, IK1, IKACh and IKNa. The incidence of clinical torsade de pointes (TdP) associated with amiodarone has been reported to be low and the present study compared the proarrhythmic potential of amiodarone with that of a selective IKr channel blocker, sematilide, using a canine chronic atrioventrucular block model. Amiodarone or sematilide (3 and 30 mg/kg; n=4 for each group) was administered orally without anesthesia under continuous ECG monitoring. Both drugs prolonged the QT interval, although the onset was faster for sematilide. The high dose of sematilide induced TdP in 3 of 4 animals, which caused their death, but neither the low dose of sematilide nor the 2 dosages of amiodarone induced lethal ventricular arrhythmias. These results suggest that IKr channel inhibition by amiodarone with its additional ion channel blocking action may contribute to the prevention of TdP.
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Affiliation(s)
- Hiroshi Yoshida
- Department of Pharmacology, Yamanashi Medical University, Nakakoma-gun, Japan
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Sugiyama A, Hashimoto K. Effects of a typical I(Kr) channel blocker sematilide on the relationship between ventricular repolarization, refractoriness and onset of torsades de pointes. JAPANESE JOURNAL OF PHARMACOLOGY 2002; 88:414-21. [PMID: 12046984 DOI: 10.1254/jjp.88.414] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The effects of a typical I(Kr) channel blocker sematilide on the relationship between ventricular repolarization, refractoriness and onset of torsades de pointes (TdP) were studied using the canine isolated, blood-perfused ventricular septum preparation with monophasic action potential (MAP) recording. Intracoronary infusion of sematilide (10-100 microg/min) prolonged the repolarization phase and effective refractory period, the extent of which was greater in the former than in the latter, resulting in prolongation of terminal repolarization process. Prolonging the basic pacing cycle length from 400 to 600 ms and/or increasing the drug doses enhanced each of these actions. Reverse use-dependence was obvious in the drug-induced prolongation of MAP duration, but it was less clear in the effective refractory period. More importantly, during sematilide infusion, in preparations paced at longer basic cycle length of 600 - 2000 ms, TdP-like polymorphic ventricular tachycardia was repeatedly induced by an extra-stimulus applied on the terminal repolarization phase, which indicates the appearance of electrically vulnerable period. Prolonging the basic pacing cycle length and/or increasing the drug doses prolonged this electrically vulnerable period in parallel with the terminal repolarization phase. These results suggest that prolongation of the terminal repolarization process by sematilide would enhance the chance of conduction slowing at less complete repolarization levels, which may be associated with a high incidence of TdP induction.
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Affiliation(s)
- Atsushi Sugiyama
- Department of Pharmacology, Yamanashi Medical University, Japan.
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Tokuno T, Muraki K, Watanabe M, Imaizumi Y. Effects of K+ channel modulators on the relationship between action potential duration and Ca2+ transients in single ventricular myocytes of the guinea pig. JAPANESE JOURNAL OF PHARMACOLOGY 1999; 80:243-53. [PMID: 10461770 DOI: 10.1254/jjp.80.243] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Effects of K+ channel modulators, cromakalim and E4031 [1-[2-(6-methyl-2-pyridyl)-ethyl]-4-(4-methylsulfonylaminobenzoyl) piperidine], on the relationship between the action potential duration (APD) and Ca2+ transients were examined in single myocytes isolated from guinea pig cardiac left ventricle. Application of cromakalim decreased APD at 90% repolarization (APD90) and Ca2+ transient elicited at 0.5 Hz (IC50s=0.6 and 3 microM, respectively). Application of 0.3 microM E4031 increased these parameters by 110% and 45%, respectively. Under voltage-clamp, the relation between the duration of depolarization to 0 mV and Ca2+ transients could be described by the sum of two exponential components; the time constants were approximately 5 and 280 msec, respectively. The first component was abolished by 10 microM ryanodine, suggesting the involvement of Ca2+-induced Ca2+ release (CICR). Neither cromakalim nor E4031 directly affected Ca2+ current and Ca2+ transients under voltage clamp. When APD was changed by K+ channel modulators, the relation between APD90 and Ca2+-transients was almost similar to that obtained by changing the depolarization duration under voltage-clamp. CICR was changed significantly only when APD90 was markedly shortened by cromakalim. The extensively prolonged AP and Ca2+ transient in the presence of E4031 were reduced by an addition of cromakalim. It is concluded that these two K+ channel modulators can significantly alter the AP-induced Ca2+ transient mainly by changing APD, which regulates both Ca2+ influx and extrusion.
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Affiliation(s)
- T Tokuno
- Department of Pharmacology & Therapeutics, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
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