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Kamsani SH, Middeldorp ME, Chiang G, Stefil M, Evans S, Nguyen MT, Shahmohamadi E, Zhang JQ, Roberts-Thomson KC, Emami M, Young GD, Sanders P. Safety of outpatient commencement of sotalol. Heart Rhythm O2 2024; 5:341-350. [PMID: 38984365 PMCID: PMC11228273 DOI: 10.1016/j.hroo.2024.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024] Open
Abstract
Background Inpatient monitoring is recommended for sotalol initiation. Objective The purpose of this study was to assess the safety of outpatient sotalol commencement. Methods This is a multicenter, retrospective, observational study of patients initiated on sotalol in an outpatient setting. Serial electrocardiogram monitoring at day 3, day 7, 1 month, and subsequently as clinically indicated was performed. Corrected QT (QTc) interval and clinical events were evaluated. Results Between 2008 and 2023, 880 consecutive patients who were commenced on sotalol were evaluated. Indications were atrial fibrillation/flutter in 87.3% (n = 768), ventricular arrhythmias in 9.9% (n = 87), and other arrhythmias in 2.8% (n = 25). The daily dosage at initiation was 131.0 ± 53.2 mg/d. The QTc interval increased from baseline (431 ± 32 ms) to 444 ± 37 ms (day 3) and 440 ± 33 ms (day 7) after sotalol initiation (P < .001). Within the first week, QTc prolongation led to the discontinuation of sotalol in 4 and dose reduction in 1. No ventricular arrhythmia, syncope, or death was observed during the first week. Dose reduction due to asymptomatic bradycardia occurred in 3 and discontinuation due to dyspnea in 3 within the first week. Overall, 1.1% developed QTc prolongation (>500 ms/>25% from baseline); 4 within 3 days, 1 within 1 week, 4 within 60 days, and 1 after >3 years. Discontinuation of sotalol due to other adverse effects occurred in 41 patients within the first month of therapy. Conclusion Sotalol initiation in an outpatient setting with protocolized follow-up is safe, with no recorded sotalol-related mortality, ventricular arrhythmias, or syncope. There was a low incidence of significant QTc prolongation necessitating discontinuation within the first month of treatment. Importantly, we observed a small incidence of late QT prolongation, highlighting the need for vigilant outpatient surveillance of individuals on sotalol.
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Affiliation(s)
- Suraya H. Kamsani
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
- Department of Cardiology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- National Heart Institute, Kuala Lumpur, Malaysia
| | - Melissa E. Middeldorp
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
- Department of Cardiology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Glenda Chiang
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
| | - Maria Stefil
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
- Department of Cardiology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Shaun Evans
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
- Department of Cardiology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Mau T. Nguyen
- Department of Cardiology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Elnaz Shahmohamadi
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
| | - Jessica Qingying Zhang
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
| | - Kurt C. Roberts-Thomson
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
- Department of Cardiology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Mehrdad Emami
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
- Department of Cardiology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Glenn D. Young
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
- Department of Cardiology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Prashanthan Sanders
- Centre for Heart Rhythm Disorders, University of Adelaide, Adelaide, South Australia, Australia
- Department of Cardiology, Royal Adelaide Hospital, Adelaide, South Australia, Australia
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Augustin N, Alvarez C, Kluger J. The Arrhythmogenicity of Sotalol and its Role in Heart Failure: A Literature Review. J Cardiovasc Pharmacol 2023; 82:86-92. [PMID: 37229640 DOI: 10.1097/fjc.0000000000001439] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 05/10/2023] [Indexed: 05/27/2023]
Abstract
ABSTRACT According to the American Heart Association, approximately 6 million adults have been afflicted with heart failure in the United States in 2020 and are more likely to have sudden cardiac death accounting for approximately 50% of the cause of mortality. Sotalol is a nonselective β-adrenergic receptor antagonist with class III antiarrhythmic properties that has been mostly used for atrial fibrillation treatment and suppressing recurrent ventricular tachyarrhythmias. The use of sotalol in patients with left ventricular dysfunction is not recommended by the American College of Cardiology or American Heart Association because studies are inconclusive with conflicting results regarding safety. This article aims to review the mechanism of action of sotalol, the β-blocking effects on heart failure, and provide an overview of clinical trials on sotalol use and its effects in patients with heart failure. Small- and large-scale clinical trials have been controversial and inconclusive about the use of sotalol in heart failure. Sotalol has been shown to reduce defibrillation energy requirements and reduce shocks from implantable cardioverter-defibrillators. Torsades de Pointes is the most life-threatening arrhythmia that has been documented with sotalol use and occurs more commonly in women and heart failure patients. Thus far, mortality benefits have not been demonstrated with sotalol use and larger multicenter studies are required going forward.
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Affiliation(s)
- Najwan Augustin
- University of Connecticut Primary Care Internal Medicine Residency, New Britain, CT; and
| | - Chikezie Alvarez
- Hartford Healthcare Heart and Vascular Institute, Hartford Hospital, Hartford, CT
| | - Jeffrey Kluger
- Hartford Healthcare Heart and Vascular Institute, Hartford Hospital, Hartford, CT
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Premuzic Mestrovic I, Smoday IM, Kalogjera L, Krezic I, Zizek H, Vranes H, Vukovic V, Oroz K, Skorak I, Brizic I, Hriberski K, Novosel L, Kavelj I, Barisic I, Beketic Oreskovic L, Zubcic S, Strbe S, Mestrovic T, Pavic P, Staresinic M, Skrtic A, Boban Blagaic A, Seiwerth S, Sikiric P. Antiarrhythmic Sotalol, Occlusion/Occlusion-like Syndrome in Rats, and Stable Gastric Pentadecapeptide BPC 157 Therapy. Pharmaceuticals (Basel) 2023; 16:977. [PMID: 37513889 PMCID: PMC10383471 DOI: 10.3390/ph16070977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 07/01/2023] [Accepted: 07/04/2023] [Indexed: 07/30/2023] Open
Abstract
We focused on the first demonstration that antiarrhythmics, particularly class II and class III antiarrhythmic and beta-blocker sotalol can induce severe occlusion/occlusion-like syndrome in rats. In this syndrome, as in similar syndromes with permanent occlusion of major vessels, peripheral and central, and other similar noxious procedures that severely disable endothelium function, the stable gastric pentadecapeptide BPC 157-collateral pathways activation, was a resolving therapy. After a high dose of sotalol (80 mg/kg intragastrically) in 180 min study, there were cause-consequence lesions in the brain (swelling, intracerebral hemorrhage), congestion in the heart, lung, liver, kidney, and gastrointestinal tract, severe bradycardia, and intracranial (superior sagittal sinus), portal and caval hypertension, and aortal hypotension, and widespread thrombosis, peripherally and centrally. Major vessels failed (congested inferior caval and superior mesenteric vein, collapsed azygos vein). BPC 157 therapy (10 µg, 10 ng/kg given intragastrically at 5 min or 90 min sotalol-time) effectively counteracted sotalol-occlusion/occlusion-like syndrome. In particular, eliminated were heart dilatation, and myocardial congestion affecting coronary veins and arteries, as well as myocardial vessels; eliminated were portal and caval hypertension, lung parenchyma congestion, venous and arterial thrombosis, attenuated aortal hypotension, and centrally, attenuated intracranial (superior sagittal sinus) hypertension, brain lesions and pronounced intracerebral hemorrhage. Further, BPC 157 eliminated and/or markedly attenuated liver, kidney, and gastrointestinal tract congestion and major veins congestion. Therefore, azygos vein activation and direct blood delivery were essential for particular BPC 157 effects. Thus, preventing such and similar events, and responding adequately when that event is at risk, strongly advocates for further BPC 157 therapy.
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Affiliation(s)
| | - Ivan Maria Smoday
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Luka Kalogjera
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Ivan Krezic
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Helena Zizek
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Hrvoje Vranes
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Vlasta Vukovic
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Katarina Oroz
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Ivan Skorak
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Ivan Brizic
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Klaudija Hriberski
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Luka Novosel
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Ivana Kavelj
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Ivan Barisic
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | | | - Slavica Zubcic
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Sanja Strbe
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Tomislav Mestrovic
- Department of Surgery, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Predrag Pavic
- Department of Surgery, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Mario Staresinic
- Department of Surgery, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Anita Skrtic
- Department of Pathology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Alenka Boban Blagaic
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Sven Seiwerth
- Department of Pathology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
| | - Predrag Sikiric
- Department of Pharmacology, School of Medicine University of Zagreb, 10000 Zagreb, Croatia
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Echocardiographic and electrocardiographic effects of atenolol versus sotalol in dogs with severe subaortic stenosis. J Vet Cardiol 2022; 41:199-208. [DOI: 10.1016/j.jvc.2022.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/13/2022] [Accepted: 03/14/2022] [Indexed: 11/19/2022]
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Gagno G, Zoppo F. Insights on arrhythmia termination and type 2 breaks after ICD therapy delivery. Pacing Clin Electrophysiol 2020; 43:1039-1047. [DOI: 10.1111/pace.14030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/15/2020] [Accepted: 08/02/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Giulia Gagno
- Dipartimento di Cardiologia Università degli Studi di Trieste, Azienda Sanitaria Universitaria Giuliano, Isontina Trieste Italy
| | - Franco Zoppo
- Elettrofisiologia, Unità Operativa di Cardiologia, Ospedale Civile di Gorizia Azienda Sanitaria Universitaria Giuliano, Isontina Trieste Italy
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Treseder JR, LeBlanc NL, Scollan KF. Inotropic and chronotropic effects of sotalol in healthy dogs. J Vet Cardiol 2019; 25:14-24. [PMID: 31442634 DOI: 10.1016/j.jvc.2019.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 07/09/2019] [Accepted: 07/16/2019] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Sotalol is an anti-arrhythmic drug commonly used for the treatment of pathologic tachyarrhythmias in dogs. The β-adrenergic blockade associated with sotalol administration may result in reduced myocardial contractility, which is clinically relevant for treating dogs with arrhythmias and concurrent myocardial dysfunction. The inotropic properties of sotalol are not well characterized in dogs. ANIMALS, MATERIALS, AND METHODS Ten healthy, adult, large breed dogs were prospectively enrolled. All dogs underwent physical examination, blood pressure measurement, electrocardiography, 24-h Holter monitoring, and echocardiography including three-dimensional left ventricular volume measurements. Dogs were subsequently administered sotalol (1-2 mg/kg) orally twice daily for 12-16 days, and the same diagnostic tests were performed. Paired statistical analysis was used to compare parameters at baseline and after treatment with sotalol. RESULTS Standard echocardiographic parameters of systolic function were reduced on sotalol compared to baseline, including ejection fraction via Simpson's method of disks which was 5.8% (95% confidence interval [CI]: 2.77-8.83%, p = 0.002) lower post-treatment. Maximum heart rate on Holter monitor was 17 bpm (95% CI: 9-37 bpm, p = 0.002) lower post-treatment than at baseline. CONCLUSIONS Sotalol has a mild negative inotropic effect in healthy dogs based on standard echocardiographic measurements. There is also a negative chronotropic effect at higher heart rates based on 24-h Holter monitoring.
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Affiliation(s)
- J R Treseder
- Oregon State University, Carlson College of Veterinary Medicine, Department of Clinical Sciences, 105 Magruder Hall, 700 SW 30th Street, Corvallis, Oregon, 97331, USA
| | - N L LeBlanc
- Oregon State University, Carlson College of Veterinary Medicine, Department of Clinical Sciences, 105 Magruder Hall, 700 SW 30th Street, Corvallis, Oregon, 97331, USA.
| | - K F Scollan
- Oregon State University, Carlson College of Veterinary Medicine, Department of Clinical Sciences, 105 Magruder Hall, 700 SW 30th Street, Corvallis, Oregon, 97331, USA
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Ishizaka T, Yoshimatsu Y, Maeda Y, Chiba K, Mori K. Negative lusitropic property of nifekalant identified using ventricular pressure-volume loop analyses in anesthetized monkeys. Exp Anim 2019; 68:91-102. [PMID: 30333366 PMCID: PMC6389513 DOI: 10.1538/expanim.18-0098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The present study was conducted to clarify multiple cardiohemodynamic and
electrophysiological properties including inotropic/lusitropic effects of nifekalant, a
class III antiarrhythmic drug, in an isoflurane-anesthetized monkey. Nifekalant was
administered intravenously at the therapeutic dose of 0.3 mg/kg over 10 min to male
cynomolgus monkeys (n=4), followed by higher dose of 1 (n=3) or 3 mg/kg (n=1) that was
limited due to arrythmogenicity. Left ventricular (LV) pressure-volume (PV) analysis
revealed that the 0.3 mg/kg dose of nifekalant induced a negative lusitropic effect,
recognized as a decrease in maximal rate of reduction in LV pressure and a prolonged
isovolumic relaxation time. Nifekalant also decreased heart rate and increased LV
end-diastolic pressure, but had no effects on the other cardiohemodynamic parameters
examined. Electrophysiological analysis showed nifekalant at 0.3 mg/kg prolonged QT/QTc
intervals with no evidence of arrhythmia. Higher doses of nifekalant induced ventricular
arrhythmia in 3 out of 4 animals, in which both the short-term and long-term variability
of the QT interval increased just before the occurrence of arrhythmia. In conclusion, a
therapeutic dose of nifekalant had no effect on inotropic activity or cardiac compliance,
whereas it showed negative lusitropic properties and QT/QTc prolongation in
isoflurane-anesthetized monkeys. In addition, higher doses of nifekalant showed remarkable
QT/QTc prolongation leading to arrhythmogenicity, which showed good accordance with
clinical findings. Caution should be paid to negative lusitropic properties as well as
arrhythmogenisity for the safe use of nifekalant.
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Affiliation(s)
- Tomomichi Ishizaka
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Yu Yoshimatsu
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Yu Maeda
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Katsuyoshi Chiba
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
| | - Kazuhiko Mori
- Medicinal Safety Research Laboratories, Daiichi Sankyo Co., Ltd., 1-16-13 Kita-Kasai, Edogawa-ku, Tokyo 134-8630, Japan
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Best Clinical Practice: Emergency Medicine Management of Stable Monomorphic Ventricular Tachycardia. J Emerg Med 2017; 52:484-492. [DOI: 10.1016/j.jemermed.2016.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/26/2016] [Accepted: 09/05/2016] [Indexed: 11/21/2022]
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Promising approach for the preclinical assessment of cardiac risks using left ventricular pressure-volume loop analyses in anesthetized monkeys. J Pharmacol Toxicol Methods 2017; 84:1-10. [DOI: 10.1016/j.vascn.2016.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/07/2016] [Accepted: 10/12/2016] [Indexed: 11/23/2022]
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Feng Z, Yu S, Liu W, Yang L, Liu Y, Zhai S, Wang F, Zhang X. A simple and sensitive LC-MS/MS method for the determination of sotalol in rat plasma. Biomed Chromatogr 2015; 29:1167-72. [PMID: 25582386 DOI: 10.1002/bmc.3403] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/28/2014] [Accepted: 11/04/2014] [Indexed: 11/09/2022]
Affiliation(s)
- Zhiping Feng
- Department of Pharmacy; Peking University Third Hospital; Beijing 100191 China
- Department of Pharmacy; Jiangmen Central Hospital Affiliated Jiangmen Hospital of Sun Yat-Sen; Jiangmen City Guangdong Province 529000 China
| | - Siyuan Yu
- Department of Pharmacy; Peking University Third Hospital; Beijing 100191 China
- Department of Pharmacy; Jiangmen Central Hospital Affiliated Jiangmen Hospital of Sun Yat-Sen; Jiangmen City Guangdong Province 529000 China
| | - Wei Liu
- Department of Pharmacy; Peking University Third Hospital; Beijing 100191 China
| | - Li Yang
- Department of Pharmacy; Peking University Third Hospital; Beijing 100191 China
| | - Yang Liu
- Department of Pharmacy; Peking University Third Hospital; Beijing 100191 China
| | - Suodi Zhai
- Department of Pharmacy; Peking University Third Hospital; Beijing 100191 China
| | - Fang Wang
- Department of Pharmacy; Jiangmen Central Hospital Affiliated Jiangmen Hospital of Sun Yat-Sen; Jiangmen City Guangdong Province 529000 China
| | - Xianhua Zhang
- Department of Pharmacy; Peking University Third Hospital; Beijing 100191 China
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Baumert M, Starc V, Porta A. Conventional QT variability measurement vs. template matching techniques: comparison of performance using simulated and real ECG. PLoS One 2012; 7:e41920. [PMID: 22860030 PMCID: PMC3408402 DOI: 10.1371/journal.pone.0041920] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Accepted: 06/29/2012] [Indexed: 12/14/2022] Open
Abstract
Increased beat-to-beat variability in the QT interval (QTV) of ECG has been associated with increased risk for sudden cardiac death, but its measurement is technically challenging and currently not standardized. The aim of this study was to investigate the performance of commonly used beat-to-beat QT interval measurement algorithms. Three different methods (conventional, template stretching and template time shifting) were subjected to simulated data featuring typical ECG recording issues (broadband noise, baseline wander, amplitude modulation) and real short-term ECG of patients before and after infusion of sotalol, a QT interval prolonging drug. Among the three algorithms, the conventional algorithm was most susceptible to noise whereas the template time shifting algorithm showed superior overall performance on simulated and real ECG. None of the algorithms was able to detect increased beat-to-beat QT interval variability after sotalol infusion despite marked prolongation of the average QT interval. The QTV estimates of all three algorithms were inversely correlated with the amplitude of the T wave. In conclusion, template matching algorithms, in particular the time shifting algorithm, are recommended for beat-to-beat variability measurement of QT interval in body surface ECG. Recording noise, T wave amplitude and the beat-rejection strategy are important factors of QTV measurement and require further investigation.
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Affiliation(s)
- Mathias Baumert
- School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, Australia.
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Tabo M, Hara T, Sone S, Shishido N, Kuramoto S, Nakano K, Onodera H, Kimura K, Kobayashi K. Prediction of drug-induced QT interval prolongation in telemetered common marmosets. J Toxicol Sci 2008; 33:315-25. [PMID: 18670163 DOI: 10.2131/jts.33.315] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Drug-induced QT interval prolongation is a critical issue in development of new chemical entities, so the pharmaceutical industry needs to evaluate risk as early as possible. Common marmosets have been in the limelight in early-stage development due to their small size, which requires only a small amount of test drug. The purpose of this study was to determine the utility of telemetered common marmosets for predicting drug-induced QT interval prolongation. Telemetry transmitters were implanted in common marmosets (male and female), and QT and RR intervals were measured. The QT interval was corrected for the RR interval by applying Bazett's and Fridericia's correction formulas and individual rate correction. Individual correction showed the least slope for the linear regression of corrected QT (QTc) intervals against RR intervals, indicating that it dissociated changes in heart rate most effectively. With the individual correction method, the QT-prolonging drugs (astemizole, dl-sotalol) showed QTc interval prolongations and the non-QT-prolonging drugs (dl-propranolol, nifedipine) did not show QTc interval prolongations. The plasma concentrations of astemizole and dl-sotalol associated with QTc interval prolongations in common marmosets were similar to those in humans, suggesting that the sensitivity of common marmosets would be appropriate for evaluating risk of drug-induced QT interval prolongation. In conclusion, telemetry studies in common marmosets are useful for predicting clinical QT prolonging potential of drugs in early stage development and require only a small amount of test drug.
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Affiliation(s)
- Mitsuyasu Tabo
- Safety Assessment Department, Research Division, Chugai Pharmaceutical Co., Ltd., Shizuoka.
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Ishizaka T, Takahara A, Iwasaki H, Mitsumori Y, Kise H, Nakamura Y, Sugiyama A. Comparison of electropharmacological effects of bepridil and sotalol in halothane-anesthetized dogs. Circ J 2008; 72:1003-11. [PMID: 18503230 DOI: 10.1253/circj.72.1003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Bepridil is known to have a multiple ion channel-blocking property in the heart, which has been applied for the treatment of atrial fibrillation and drug-refractory ventricular tachyarrhythmias. In this study, the electro-pharmacological effects of bepridil were compared with those of dl-sotalol, a representative class III antiarrhythmic drug, using the halothane-anesthetized canine model. METHODS AND RESULTS Cardiovascular and electrophysiological variables were measured under the halothane anesthesia. Intravenous administration of bepridil (0.3 mg/kg, n=4) delayed the intraventricular conduction and prolonged the ventricular effective refractory period, whereas dl-sotalol (0.3 mg/kg, iv, n=4) inhibited atrioventricular conduction and prolonged the atrial and ventricular effective refractory period. The additional administration of 10 times the higher dose of bepridil or dl-sotalol (ie, 3 mg/kg, iv, n=4 for each group) decreased blood pressure, suppressed ventricular contraction and sinus automaticity, and prolonged the atrial and ventricular effective refractory period and monophasic action potential duration, in addition to the effects of the low dose. CONCLUSIONS The electropharmacological effects of bepridil and dl-sotalol were similar, although their potency for each cardiovascular variable varied significantly. These findings can be useful when selecting these drugs according to the pathophysiological condition of a patient.
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Affiliation(s)
- Tomomichi Ishizaka
- Department of Pharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Japan
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Bourque D, Daoust R, Huard V, Charneux M. β-Blockers for the treatment of cardiac arrest from ventricular fibrillation? Resuscitation 2007; 75:434-44. [PMID: 17764805 DOI: 10.1016/j.resuscitation.2007.05.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2007] [Revised: 05/01/2007] [Accepted: 05/09/2007] [Indexed: 10/22/2022]
Abstract
More than 160,000 people suffer sudden cardiac death each year in the US. It is estimated that ventricular fibrillation (VF) is the initial rhythm in approximately 30% of these cases. Ventricular fibrillation that does not respond to the first few defibrillation attempts is associated with mortality rates of up to 97%. Currently, no pharmacological intervention has been shown to increase long-term survival in patients with shock-refractory VF. The purpose of this review article is to evaluate whether beta-blocker administration during the resuscitation of cardiac arrest from VF or pulseless ventricular tachycardia (VT) improves outcome. We searched the MEDLINE and EMBASE databases for human clinical trials, animal experimental trials, review articles, case reports and abstracts published between 1966 and September 2006. No human prospective randomized controlled trial has studied the effects of beta-blocker administration during VF directly. Prospective trials of anti-arrhythmics with beta-blocking properties have been published, as well as several case reports/case series and experimental animal studies. The evidence thus far suggests that beta-blockade during resuscitation from VF may be associated with increasing rates of resuscitation, greater post-resuscitation survival, and improved post-resuscitation myocardial function. These positive effects on outcome may be mediated by a decrease in the oxygen requirements of the fibrillating heart, thus improving the overall balance between myocardial oxygen supply and demand during resuscitation. While no significant detrimental effects directly related to low dose beta-blockade during VF have been reported in the studies reviewed, concerns relating to possible loss of myocardial contractility and hypotension remain. To this day, high quality human trials are lacking. Preliminary human studies are needed to assess the effects of beta-blockers in the treatment of cardiac arrest from ventricular fibrillation or pulseless VT further.
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Affiliation(s)
- Daniel Bourque
- Department of Emergency Medicine, Sacré-Coeur Hospital, 5400 Gouin Ouest, Montreal, Quebec, Canada H4J 1C5.
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Li J, Wang JA. The effects of sotalol on ventricular repolarization during exercise. J Zhejiang Univ Sci B 2005; 6:249-53. [PMID: 15754421 PMCID: PMC1389732 DOI: 10.1631/jzus.2005.b0249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Although after pacing animal and human studies have demonstrated a rate-dependent effect of sotalol on ventricular repolarization, there is little information on the effects of sotalol on ventricular repolarization during exercise. This study attempted to show the effects of sotalol on ventricular repolarization during physiological exercise. METHODS Thirty-one healthy volunteers (18 males, 13 females) were enrolled in the study. Each performed a maximal treadmill exercise test according to the Bruce protocol after random treatment with sotalol, propranolol and placebo. RESULTS Sotalol significantly prolonged QTc (corrected QT) and JTc (corrected JT) intervals at rest compared with propranolol (QTc 324.86 ms vs 305.21 ms, P<0.001; JTc 245.04 ms vs 224.17 ms, P<0.001) and placebo (QTc 324.86 ms vs 314.06 ms, P<0.01; JTc 245.04 ms vs. 232.69 ms, P<0.001). The JTc percent reduction increased progressively with each stage of exercise and correlated positively with exercise heart rate (r=0.148, P<0.01). The JTc percent reduction correlation with exercise heart rate did not exist with either propranolol or placebo. CONCLUSIONS These results imply that with sotalol ventricular repolarization is progressively shortened after exercise. Thus the specific class III antiarrhythmic activity of sotalol, present as delay of ventricular repolarization, may be attenuated during exercise. Such findings may imply the need to consider other antiarrythmic therapy during periods of stress-induced tachycardia.
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Affiliation(s)
- Jian Li
- Cardiology Department of Pu Nan Hospital, Pudong New District, Shanghai 200125, China
- †E-mail:lj.zj @126.com;
| | - Jian-an Wang
- Cardiology Department of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, China
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16
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Hirose M, Miura M, Wakayama Y, Endo H, Sugai Y, Stuyvers BDMY, Kagaya Y, Watanabe J, ter Keurs HEDJ, Shirato K. Effect of Nifekalant, a Class III Anti-Arrhythmic Agent, on Ca2+ Waves in Rat Intact Trabeculae. Circ J 2005; 69:739-45. [PMID: 15914955 DOI: 10.1253/circj.69.739] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Nifekalant, a class III anti-arrhythmic agent, has been used clinically at serum concentrations of 1-10 micromol/L in patients with ventricular arrhythmias. However, the effect of nifekalant on triggered arrhythmias has not yet been established. METHODS AND RESULTS Trabeculae were dissected from the right ventricles of 16 rat hearts. The force was measured using a silicon strain gauge, the membrane potential using ultra-compliant microelectrodes, and the regional intracellular Ca2+ ([Ca2+]i) using electrophoretically microinjected fura-2 and an image intensified CCD camera at a sarcomere length of 2.1 microm. Rapid cooling contractures (RCCs) were measured to estimate the Ca2+ content in the sarcoplasmic reticulum. Ca2+ waves and aftercontractions were measured after the induction of reproducible Ca2+ waves. Nifekalant at 1, 10 and 250 micromol/L increased significantly the action potential duration, the peak [Ca2+]i, the developed force and the amplitude of RCCs in a concentration-dependent manner (stimulus interval = 2 s, [Ca2+]o = 0.7 mmol/L, 26.0+/-0.2 degrees C). Nifekalant at 10 and 250 micromol/L increased significantly the velocity of Ca2+ waves with an enhancement of the aftercontractions (stimulus interval = 0.5 s for 7.5 s, [Ca2+]o = 1.8+/-0.1 mmol/L, 22.3+/-0.5 degrees C). CONCLUSIONS Nifekalant, even at a therapeutic concentration, can increase muscle contraction, but may worsen triggered arrhythmias because of the acceleration of Ca2+ waves under Ca2+-overloaded conditions.
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Affiliation(s)
- Masanori Hirose
- Department of Cardiovascular Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan
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17
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Manoach M, Tribulova N. Sotalol: the mechanism of its antiarrhythmic-defibrillating effect. CARDIOVASCULAR DRUG REVIEWS 2002; 19:172-82. [PMID: 11484069 DOI: 10.1111/j.1527-3466.2001.tb00062.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This minireview deals with the role of intercellular communication and synchronization in the initiation and maintenance of ventricular fibrillation. It is proposed that myocardial cell junctions might represent a therapeutic substrate for the prevention of this fatal arrhythmia. This hypothesis is supported by the results of recent experimental studies involving elucidation of the mechanism of antiarrhythmic-defibrillating effects of sotalol. Enhancement of intercellular communication and myocardial synchronization are thought to play critical role in the mechanism of action of this drug.
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Affiliation(s)
- M Manoach
- Department of Physiology and Pharmacology, Tel Aviv University Medical School, Tel Aviv, Israel
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18
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Manoach M, Varon D, Tribulova N, Shainberg A, Zinman T, Isaack A, Imanaga I. Are the antiarrhythmic-defibrillating effects of D-sotalol due to or despite the prolongation of the action potential duration? Life Sci 1999; 65:PL273-9. [PMID: 10622238 DOI: 10.1016/s0024-3205(99)00520-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
These results support our hypothesis that class III compounds, with a positive inotropic effect, increase intercellular coupling and synchronization, mainly by preventing intracellular Ca overload. They act as defibrillating compound, similar to cAMP and adrenaline, most probably due to their so called sympathomimetic effect. In our opinion, their cardioprotective effects, resembling cardioversion, are not related to their ability to prolong APD and ERP. Moreover, we suggest that any compound that possesses these sympathomimetic effects, but without inducing the arrhythmogenic prolongation of APD, may exhibit a potent, safety and more efficient antiarrhythmic - defibrillating ability.
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19
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Abstract
Sotalol, the most recently approved oral antiarrhythmic drug, has a unique pharmacologic profile. Its electrophysiology is explained by nonselective beta-blocking action as well as class III antiarrhythmic activity (including fast-activating cardiac membrane-delayed rectifier current blockade), which leads to increases in action potential duration and refractory period throughout the heart and in QT interval on the surface electrocardiogram. Its better hemodynamic tolerance than other beta-blockers may be a result of enhanced inotropy associated with class III activity. Sotalol's ability to suppress ventricular ectopy is similar to that of class I agents and better than that of standard beta-blockers. Unlike class I agents, its use in a postinfarction trial was not associated with increased mortality rate. Therapeutically, it has shown superior efficacy for prevention of recurrent ventricular tachycardia and ventricular fibrillation, which was the basis for its approval. In a randomized study, the Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) trial, sotalol was associated with an increased in-hospital efficacy prediction rate (by Holter monitor or electrophysiologic study), reduced long-term arrhythmic recurrence rate with superior tolerance, and lower mortality rate than class I ("standard") antiarrhythmic drugs. Sotalol was 1 of 2 drugs selected for comparison with implantable defibrillators in the recent National Institutes of Health Antiarrhythmics versus Implantable Defibrillator (AVID) study. Sotalol appears to be a preferred drug for use with implantable defibrillators; unlike some other agents (eg, amiodarone) it does not elevate and, indeed, may lower defibrillation threshold. Although unapproved for this use, sotalol is active against atrial arrhythmias. It has shown efficacy equivalent to propafenone and quinidine in preventing atrial fibrillation recurrence, but it is better tolerated than quinidine and provides excellent rate control during recurrence. Sotalol's major side effects are related to beta-blockade and the risk of torsades de pointes (acceptably small if appropriate precautions are taken). Unlike several other antiarrhythmics (eg, amiodarone), it has no pharmacokinetic drug-drug interactions, is not metabolized, and is entirely renally excreted. Initial dose is 80 mg twice daily, with gradual titration to 240 to 360 mg/day as needed. The daily dose must be reduced in renal failure. On the basis of favorable clinical trials and practice experience, sotalol has shown a steadily growing impact on the treatment of arrhythmias during its 5 years of market availability, a trend that is likely to continue.
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Affiliation(s)
- J L Anderson
- University of Utah and St. Vincent'sHospital, Northside Cardiology, Salt Lake City, USA
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20
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Devereux G, Fishwick K, Aiken TC, Bourke SJ, Hendrick DJ. Adverse effects of a single dose of (+)-sotalol in patients with mild stable asthma. Br J Clin Pharmacol 1998; 46:79-82. [PMID: 9690953 PMCID: PMC1873981 DOI: 10.1046/j.1365-2125.1998.00039.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/1997] [Accepted: 01/22/1998] [Indexed: 11/20/2022] Open
Abstract
AIMS To investigate the effect of (+)-sotalol, which is not thought to possess clinically significant beta-adrenoceptor blocking activity, on airway responsiveness in subjects with mild asthma. METHODS A placebo controlled, double-blind, single dose, cross over study, evaluating the effects of oral (+)-sotalol 300 mg and oral (+/-)-sotalol 240 mg, on airway responsiveness, FEV1, and heart rate in 18 asthmatic volunteers with quantifiable levels of airway responsiveness. RESULTS Compared with placebo, (+)-sotalol induced a significant increase in airway responsiveness, and a significant decrease in FEV1, but there was no significant change in heart rate. Following (+/-)-sotalol there was no significant effect on airway responsiveness, but there were significant decreases in FEV1 and heart rate. In one subject both (+)-sotalol and (+/-)-sotalol provoked a 49% decrement in FEV1, and in another there were decrements of 20% and 18%, respectively. CONCLUSIONS Despite theoretical considerations, it cannot be assumed that (+)-sotalol is safe in patients with asthma.
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Affiliation(s)
- G Devereux
- Department of Respiratory Medicine, Royal Victoria Infirmary, University of Newcastle upon Tyne
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Abstract
Class III antiarrhythmic drugs have been under extensive clinical investigation as safer, more effective alternatives to class I drugs, which have recognized risks in selected populations. Class III drugs prolong the action potential duration of myocardial cells, resulting in a lengthening of the effective refractory period. This pharmacologic activity has antiarrhythmic properties, but it may induce a distinctive form of proarrhythmia known as torsades de pointes. Amiodarone and d,l-sotolol are class III drugs that have been available for many years. In addition to their ability to prolong refractoriness, these drugs have other pharmacodynamic properties. Recent antiarrhythmic drug discovery has focused on the identification and development of selective or so-called pure class III drugs that are devoid of additional actions. Investigators have hoped that these drugs would be as effective as sotalol and amiodarone but have fewer adverse effects. Accumulating data, however, indicate that complex compounds exhibiting antiadrenergic and other electrophysiologic properties may be superior to pure class III agents.
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Affiliation(s)
- D J MacNeil
- Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543-4000, USA
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22
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Beaufort-Krol GC, Bink-Boelkens MT. Sotalol for atrial tachycardias after surgery for congenital heart disease. Pacing Clin Electrophysiol 1997; 20:2125-9. [PMID: 9272523 DOI: 10.1111/j.1540-8159.1997.tb03642.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Atrial tachycardias, in particular atrial flutter after surgery for congenital heart disease, is associated with a high mortality. Treatment with various antiarrhythmic drugs and/or antitachycardia pacemakers is not very successful. Sotalol, a Class III drug, has shown to be a promising drug in adults with atrial tachycardias. However, the experience with sotalol in children after surgery for congenital heart disease is limited. Therefore, we describe our results here. Between December 1990 and February 1997, 26 children with atrial tachycardias, most of them with atrial flutter or fibrillation (n = 20), after surgery for congenital heart disease were treated with sotalol orally. The age of the children at the start of treatment was 7.5 +/- 5.8 years (mean +/- SD). The time interval between surgery and the start of atrial tachycardia ranged from 1 day to 14.3 years (3.8 +/- 3.8 years). Conversion to sinus rhythm was achieved in 16 out of 22 hemodynamically stable children with a dosage of 4.0 +/- 1.6 mg/kg per day. The six children without sinus rhythm on sotalol and four hemodynamically unstable patients were treated prophylactically with sotalol after DC cardioversion for their tachycardias. Two children complained of mild transient fatigue. Heart rate decreased during therapy (95 +/- 33 vs 81 +/- 21 beats/min; P = 0.01). QTc-intervals did not change. Proarrhythmias such as torsades de pointes were not encountered. Two children with a preexistent sick sinus syndrome showed aggravation of bradycardia and needed pacemaker implantation. The percentage of children with a recurrence-free interval of 1 and 2 years was 96% and 81%, respectively, for all atrial tachycardias, and 92% and 66% for atrial flutter. The recurrences of atrial tachycardias during the follow-up period, which ranged from 0.1-6.1 years (2.5 +/- 1.8 years) could be treated with only an increase of the dosage of sotalol in all but one patient. We conclude that sotalol is an effective drug for the treatment and prevention of atrial tachycardia in children after surgery for congenital heart disease.
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Affiliation(s)
- G C Beaufort-Krol
- Beatrix Children's Hospital, Division off Pediatric Cardiology, University of Groningen, The Netherlands
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Kimura M, Umemura K, Ikeda Y, Kosuge K, Mizuno A, Nakanomyo H, Ohashi K, Nakashima M. Pharmacokinetics and pharmacodynamics of (+/-)-sotalol in healthy male volunteers. Br J Clin Pharmacol 1996; 42:583-8. [PMID: 8951189 DOI: 10.1111/j.1365-2125.1996.tb00113.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. We investigated the pharmacokinetics and pharmacodynamics of (+/-)-sotalol administered orally to healthy male volunteers in single doses of 40, 80 and 160 mg and in multiple doses of 80 mg twice daily for 7 consecutive days. 2. In the single dose studies, the half-life of (-)-sotalol (7.2-8.5 h) was significantly (P < 0.01) shorter than that of (+)-sotalol (9.1-11.4 h) while the renal clearance of (-)-sotalol (110.6-126.4 ml min-1) was significantly (P < 0.01) faster than that of (+)-sotalol (102.2-110.1 ml min-1). In the multiple dose studies, similar differences in the pharmacokinetics of (+)- and (-)-sotalol were observed. In addition, the pharmacokinetics of both (+)- and (-)-sotalol on day 4 were shown to be essentially the same as those on day 7. 3. In pharmacodynamic examinations, (+/-)-sotalol prolonged QTc intervals on electrocardiograms dose-dependently after single doses of 80 and 160 mg (3.81 +/- 2.96%, 13.23 +/- 5.66%). The correlation between the plasma concentration of (+/-)-sotalol and prolongation of QTc intervals was nearly linear, and showed no hysteresis. 4. In conclusion, we demonstrated that QTc interval was prolonged with a linear correlation to the plasma concentration of (+/-)-sotalol. In addition, our study suggested that differences in the pharmacokinetics of (+)- and (-)-sotalol may be attributable to faster urinary excretion of (-)-sotalol.
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Affiliation(s)
- M Kimura
- Department of Clinical Pharmacology, Hamamatsu University School of Medicine, Kanagawa, Japan
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24
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Advani SV, Singh BN. Pharmacodynamic, pharmacokinetic and antiarrhythmic properties of d-sotalol, the dextro-isomer of sotalol. Drugs 1995; 49:664-79. [PMID: 7601009 DOI: 10.2165/00003495-199549050-00003] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In recent years, there has been a major shift from the use of antiarrhythmic drugs that act by slowing conduction to those that exert their beneficial actions by lengthening cardiac repolarisation. Such a shift is occurring because sodium channel blockers may increase mortality, especially in patients with structural heart disease, and because drugs such as sotalol and amiodarone are effective, with a potential for decreasing arrhythmic mortality. In this context, the electrophysiological and antiarrhythmic properties of d-sotalol, the dextro-isomer of sotalol, are of major importance. d-Sotalol is essentially devoid of beta-blocking actions and may be considered a pure class III compound. It has been assumed that its clinical efficacy would approximate that of amiodarone and sotalol, but without the complex adverse effect profile of amiodarone and the adverse beta-blocker effects of racemic sotalol. d-Sotalol has pharmacokinetic properties that resemble those of the racemate. It lengthens the QT/QTc interval but does not affect other electrocardiographic (ECG) intervals. It increases the refractory period in the atria, ventricles, bypass tracts and the His-Purkinje system while minimally slowing the heart rate. In preliminary studies, it had a weak suppressant effect on premature ventricular contractions, prevented inducibility of ventricular tachycardia or fibrillation in about 40% of patients, and demonstrated the potential to terminate atrial flutter and fibrillation and maintain stability of sinus rhythm during prophylactic administration. The drug exhibits little or no negative inotropic actions. Thus, it is likely to be better tolerated in patients with congestive heart failure dependent on sympathetic stimulation for compensation. Because it produces less bradycardic effect than the racemate, it is believed that the drug might induce a lower rate of torsade de pointes. The role of d-sotalol in controlling cardiac arrhythmias is being addressed in a number controlled clinical trials. However, one such double-blind, placebo-controlled trial, Survival With Oral d-Sotalol (or SWORD), in survivors of myocardial infarction with depressed ventricular function was recently terminated prematurely because of a strikingly greater all-cause mortality compared with placebo (4.6 versus 2.6%). These preliminary findings, still to be fully analysed and interpreted for clinical significance, nevertheless raise valid concerns regarding the currently popular concept of controlling cardiac arrhythmias by the selective or isolated prolongation of repolarisation ('pure' class III action) as an antiarrhythmic principle.
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