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Zhao Z, Ruan S, Ma X, Feng Q, Xie Z, Nie Z, Fan P, Qian M, He X, Wu S, Zhang Y, Zheng X. Challenges Faced with Small Molecular Modulators of Potassium Current Channel Isoform Kv1.5. Biomolecules 2019; 10:E10. [PMID: 31861703 PMCID: PMC7022446 DOI: 10.3390/biom10010010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/08/2019] [Accepted: 12/10/2019] [Indexed: 12/30/2022] Open
Abstract
The voltage-gated potassium channel Kv1.5, which mediates the cardiac ultra-rapid delayed-rectifier (IKur) current in human cells, has a crucial role in atrial fibrillation. Therefore, the design of selective Kv1.5 modulators is essential for the treatment of pathophysiological conditions involving Kv1.5 activity. This review summarizes the progress of molecular structures and the functionality of different types of Kv1.5 modulators, with a focus on clinical cardiovascular drugs and a number of active natural products, through a summarization of 96 compounds currently widely used. Furthermore, we also discuss the contributions of Kv1.5 and the regulation of the structure-activity relationship (SAR) of synthetic Kv1.5 inhibitors in human pathophysiology. SAR analysis is regarded as a useful strategy in structural elucidation, as it relates to the characteristics that improve compounds targeting Kv1.5. Herein, we present previous studies regarding the structural, pharmacological, and SAR information of the Kv1.5 modulator, through which we can assist in identifying and designing potent and specific Kv1.5 inhibitors in the treatment of diseases involving Kv1.5 activity.
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Affiliation(s)
- Zefeng Zhao
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Songsong Ruan
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Xiaoming Ma
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Qian Feng
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Zhuosong Xie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Zhuang Nie
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Peinan Fan
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Mingcheng Qian
- Department of Medicinal Chemistry, School of Pharmaceutical Engineering and Life Science, Changzhou University, Changzhou 213164, China;
- Laboratory for Medicinal Chemistry, Ghent University, Ottergemsesteenweg 460, B-9000 Ghent, Belgium
| | - Xirui He
- Department of Bioengineering, Zhuhai Campus of Zunyi Medical University, Zhuhai 519041, China;
| | - Shaoping Wu
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
| | - Yongmin Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
- Sorbonne Université, Institut Parisien de Chimie Moléculaire, CNRS UMR 8232, 4 place Jussieu, 75005 Paris, France
| | - Xiaohui Zheng
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, 229 Taibai Road, Xi’an 710069, China; (Z.Z.); (S.R.); (X.M.); (Q.F.); (Z.X.); (Z.N.); (P.F.); (Y.Z.); (X.Z.)
- Biomedicine Key Laboratory of Shaanxi Province, School of Pharmacy, Northwest University, 229 Taibai Road, Xi’an 710069, China
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Hu D, Barajas-Martínez H, Burashnikov A, Panama BK, Cordeiro JM, Antzelevitch C. Mechanisms underlying atrial-selective block of sodium channels by Wenxin Keli: Experimental and theoretical analysis. Int J Cardiol 2016; 207:326-34. [PMID: 26820362 DOI: 10.1016/j.ijcard.2016.01.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/29/2015] [Accepted: 01/01/2016] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Atrial-selective inhibition of cardiac sodium channel current (INa) and INa-dependent parameters has been shown to contribute to the safe and effective management of atrial fibrillation. The present study was designed to examine the basis for the atrial-selective actions of Wenxin Keli. METHODS Whole cell INa was recorded at room temperature in canine atrial and ventricular myocytes. Trains of 40 pulses were elicited over a range of pulse durations and interpulse intervals to determine tonic and use-dependent block. A Markovian model for INa that incorporates interaction of Wenxin Keli with different states of the channel was developed to examine the basis for atrial selectivity of the drug. RESULTS Our data indicate that Wenxin Keli does not bind significantly to either closed or open states of the sodium channel, but binds very rapidly to the inactivated state of the channel and dissociates rapidly from the closed state. Action potentials recorded from atrial and ventricular preparations in the presence of 5g/L Wenxin Keli were introduced into the computer model in current clamp mode to simulate the effects on maximum upstroke velocity (Vmax). The model predicted much greater inhibition of Vmax in atrial vs. ventricular cells at rapid stimulation rates. CONCLUSION Our findings suggest that atrial selectivity of Wenxin Keli to block INa is due to more negative steady-state inactivation, less negative resting membrane potential, and shorter diastolic intervals in atrial vs. ventricular cells at rapid activation rates. These actions of Wenxin Keli account for its relatively safe and effective suppression of atrial fibrillation.
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Affiliation(s)
- Dan Hu
- Masonic Medical Research Laboratory, Utica, NY, United States
| | | | | | - Brian K Panama
- Masonic Medical Research Laboratory, Utica, NY, United States
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Aunes M, Egstrup K, Frison L, Berggren A, Stridh M, Sörnmo L, Edvardsson N. Rapid slowing of the atrial fibrillatory rate after administration of AZD7009 predicts conversion of atrial fibrillation. J Electrocardiol 2013; 47:316-23. [PMID: 24508473 DOI: 10.1016/j.jelectrocard.2013.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Indexed: 10/25/2022]
Abstract
BACKGROUND Effects on the atrial fibrillatory rate (AFR) were studied during infusion with the combined potassium and sodium channel blocker AZD7009. METHODS AND RESULTS Patients with persistent atrial fibrillation (AF) were randomized to AZD7009 or placebo. Thirty-five patients converted to sinus rhythm (SR) and were matched to 35 non-converters. The mean AFR before conversion was 231 fibrillations per minute (fpm), having decreased by 41%; in non-converters, it was 296 fpm at the end of infusion, having decreased by 26%. The rate of decrease was greater in converters at 5 min, -88 vs. -66 fpm (p=0.02), and at 10 min, -133 vs. -111 fpm (p=0.048). The AFR-SD and the exponential decay decreased. A small left atrial area was the only baseline predictor of conversion to SR. CONCLUSIONS AZD7009 produced a significantly more rapid decrease of the AFR in converters than in non-converters, but the AFR at baseline was not predictive of conversion.
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Affiliation(s)
| | | | | | | | - Martin Stridh
- Department of Electrical and Information Technology and Center for Integrative Electrocardiology, Lund University, Lund, Sweden
| | - Leif Sörnmo
- Department of Electrical and Information Technology and Center for Integrative Electrocardiology, Lund University, Lund, Sweden
| | - Nils Edvardsson
- Sahlgrenska Academy at the Sahlgrenska University Hospital, Göteborg, Sweden
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Aunes-Jansson M, Edvardsson N, Stridh M, Sörnmo L, Frison L, Berggren A. Decrease of the atrial fibrillatory rate, increased organization of the atrial rhythm and termination of atrial fibrillation by AZD7009. J Electrocardiol 2013; 46:29-35. [DOI: 10.1016/j.jelectrocard.2012.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Indexed: 12/01/2022]
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5
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Burashnikov A, Antzelevitch C. Novel pharmacological targets for the rhythm control management of atrial fibrillation. Pharmacol Ther 2011; 132:300-13. [PMID: 21867730 PMCID: PMC3205214 DOI: 10.1016/j.pharmthera.2011.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 08/05/2011] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is a growing clinical problem associated with increased morbidity and mortality. Development of safe and effective pharmacological treatments for AF is one of the greatest unmet medical needs facing our society. In spite of significant progress in non-pharmacological AF treatments (largely due to the use of catheter ablation techniques), anti-arrhythmic agents (AADs) remain first line therapy for rhythm control management of AF for most AF patients. When considering efficacy, safety and tolerability, currently available AADs for rhythm control of AF are less than optimal. Ion channel inhibition remains the principal strategy for termination of AF and prevention of its recurrence. Practical clinical experience indicates that multi-ion channel blockers are generally more optimal for rhythm control of AF compared to ion channel-selective blockers. Recent studies suggest that atrial-selective sodium channel block can lead to safe and effective suppression of AF and that concurrent inhibition of potassium ion channels may potentiate this effect. An important limitation of the ion channel block approach for AF treatment is that non-electrical factors (largely structural remodeling) may importantly determine the generation of AF, so that "upstream therapy", aimed at preventing or reversing structural remodeling, may be required for effective rhythm control management. This review focuses on novel pharmacological targets for the rhythm control management of AF.
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Johnson DM, de Jong MMJ, Crijns HJGM, Carlsson LG, Volders PGA. Reduced ventricular proarrhythmic potential of the novel combined ion-channel blocker AZD1305 versus dofetilide in dogs with remodeled hearts. Circ Arrhythm Electrophysiol 2011; 5:201-9. [PMID: 22080293 DOI: 10.1161/circep.111.963025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AZD1305 is an investigational antiarrhythmic agent for management of atrial fibrillation. It blocks various cardiac ion currents at different potencies and has atrial-predominant electrophysiological effects. We investigated the electrophysiological and proarrhythmic effects of AZD1305 versus dofetilide in dogs with chronic complete atrioventricular block and myocardial hypertrophic remodeling. METHODS AND RESULTS AZD1305 was administered to anesthetized mongrel dogs before and >2 weeks after the induction of atrioventricular block and ventricular and atrial electrophysiological parameters were assessed. In all dogs, the selective I(Kr) blocker dofetilide was used to examine susceptibility to acquired torsades de pointes in chronic atrioventricular block and for comparison. At normal sinus rhythm, AZD1305 increased QT and RR intervals from 290±7 to 397±15 ms (+37%, P<0.0001) and from 603±22 to 778±32 ms (+29%, P=0.002), respectively. In the same animals at chronic atrioventricular block, AZD1305 increased the QT interval from 535±28 to 747±36 ms (+40%, P<0.0001), similar to the QT prolongation by dofetilide (511±22 to 703±45 ms [+38%, P<0.0001]). AZD1305 slightly slowed the idioventricular rhythm. Whereas all (n=14) chronic atrioventricular block animals exhibited torsades de pointes on dofetilide, the arrhythmia was induced in only 4 of 11 dogs after AZD1305. Beat-to-beat variability of left-ventricular monophasic-action-potential duration increased after dofetilide (2.3±0.2 to 6.3±0.7 ms; P<0.0001) but not after AZD1305 (2.8±0.3 to 3.7±0.3 ms; P=0.20) despite similar left-ventricular monophasic-action-potential duration prolongations. CONCLUSIONS Despite causing similar degrees of repolarization delay as the selective I(Kr) blocker dofetilide, the combined ion-channel blocker AZD1305 induces less repolarization instability and has a lower ventricular proarrhythmic potential in the remodeled dog heart.
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Affiliation(s)
- Daniel M Johnson
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
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Burashnikov A, Petroski A, Hu D, Barajas-Martinez H, Antzelevitch C. Atrial-selective inhibition of sodium-channel current by Wenxin Keli is effective in suppressing atrial fibrillation. Heart Rhythm 2011; 9:125-31. [PMID: 21884675 DOI: 10.1016/j.hrthm.2011.08.027] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 08/28/2011] [Indexed: 11/17/2022]
Abstract
BACKGROUND Wenxin Keli is a Chinese herb extract reported to be of benefit in the treatment of cardiac arrhythmias, cardiac inflammation, and heart failure. METHODS AND RESULTS We evaluated the electrophysiologic effects of Wenxin Keli in isolated canine arterially perfused right atrial preparations with a rim of right ventricular tissue (n = 11). Transmembrane action potentials and a pseudoelectrocardiogram were simultaneously recorded. Acetylcholine (1 μM) was used to induce atrial fibrillation (AF) and to test the anti-AF potential of Wenxin Keli (5 g/L). Wenxin Keli produced preferential abbreviation of action potential duration measured at 90% repolarization (APD(90)) in atria, but caused atrial-selective prolongation of the effective refractory period, due to the development of postrepolarization refractoriness. The maximum rate of rise of the action potential upstroke was preferentially reduced in atria. The diastolic threshold of excitation increased in both atria and ventricles, but much more in atria. The duration of the "P wave" (index of atrial conduction time) was prolonged to a much greater extent than the duration of the "QRS complex" (index of ventricular conduction time). Wenxin Keli significantly reduced I(Na) and shifted steady-state inactivation to more negative potentials in HEK293 cells stably expressing SCN5A. Wenxin Keli prevented the induction of persistent AF in 100% atria (6/6) and, in another experimental series, was found to terminate persistent acetylcholine-mediated AF in 100% of atria (3/3). CONCLUSION Wenxin Keli produces atrial-selective depression of I(Na)-dependent parameters in canine isolated coronary-perfused preparations via a unique mechanism and is effective in suppressing AF and preventing its induction, with minimal effects on the ventricular electrophysiology.
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Egstrup K, Bergfeldt L, Duris T, Gullestad L, Kochmanski M, Kuśnierz B, Nielsen T, Sawicki S, Aunes-Jansson M, Edvardsson N, Frison L, Johansson S, Berggren A. QT Response after a Test Dose and during Maintenance Therapy with AZD1305 in Patients with Atrial Fibrillation. Am J Cardiovasc Drugs 2011; 11:199-208. [DOI: 10.2165/11591750-000000000-00000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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9
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Rónaszéki A, Alings M, Egstrup K, Gaciong Z, Hranai M, Király C, Sereg M, Figatowski W, Bondarov P, Johansson S, Frison L, Edvardsson N, Berggren A. Pharmacological cardioversion of atrial fibrillation--a double-blind, randomized, placebo-controlled, multicentre, dose-escalation study of AZD1305 given intravenously. Europace 2011; 13:1148-56. [PMID: 21561900 DOI: 10.1093/europace/eur120] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIM AZD1305 is a combined ion channel blocker developed for the treatment of atrial fibrillation (AF). The aim of this study was to determine whether AZD1305 was effective in converting AF to sinus rhythm (SR). METHODS AND RESULTS Patients with AF episodes of duration 3 h to 3 months were randomized in a 3:1 ratio to receive a maximum 30 min intravenous infusion of AZD1305 or matching placebo. The primary efficacy endpoint was the proportion of patients converting within 90 min of the start of infusion, after which patients who had not converted were to undergo direct current (DC) cardioversion. Four ascending AZD1305 dose groups were assigned sequentially, with dose rates of 50, 100, 130, and 180 mg/h. A total of 171 patients were randomized. Pharmacological conversion was achieved in 0 of 43 patients (0%) in the placebo group, and in 2 of 26 (8%; P= 0.14 vs. placebo), 8 of 45 (18%; P= 0.006), 17 of 45 (38%; P< 0.001), and 6 of 12 patients (50%; P< 0.001) in AZD1305 dose groups 1-4, respectively. Maximum QTcF (QT interval corrected according to Fridericia's formula) generally increased dose-dependently up to a plateau, although there was wide variation between patients. Two patients experienced torsade de pointes (TdP): one patient without symptoms in dose group 3, and one patient requiring DC defibrillation in dose group 4. Both patients recovered without sequelae. CONCLUSIONS AZD1305 was effective in converting AF to SR, but was associated with QT prolongation and TdP. The benefit-risk profile was judged as unfavourable and the AZD1305 development programme was discontinued. CLINICAL TRIAL REGISTRATION http://clinicaltrials.gov identifier NCT00915356.
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Rhythm control strategies and the role of antiarrhythmic drugs in the management of atrial fibrillation: focus on clinical outcomes. J Gen Intern Med 2011; 26:531-7. [PMID: 21108047 PMCID: PMC3077493 DOI: 10.1007/s11606-010-1574-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 09/13/2010] [Accepted: 10/20/2010] [Indexed: 10/18/2022]
Abstract
Atrial fibrillation (AF) is a common disorder that significantly impacts the lives of affected patients. The restoration of sinus rhythm may prevent AF progression and reduce the occurrence of negative sequelae; however, available antiarrhythmic drugs (AADs) have largely failed to demonstrate significant benefit relative to rate control with respect to morbidity and mortality outcomes. The review commentary will address current knowledge regarding the pathologic mechanisms of AF, current trials that investigate rate and rhythm strategies, and future therapies that may change treatment approaches based on preliminary evidence suggesting a more favorable safety profile. The observed outcomes are likely a reflection of the limited efficacy plus poor safety and tolerability of available AADS. However, data from patients who attained and maintained sinus rhythm in a number of clinical studies demonstrate that the achievement of normal sinus rhythm can indeed reduce AF-associated morbidity and mortality. Furthermore, the results of trials designed to assess specific morbidity and mortality outcomes such as cardiovascular death hospitalization suggest that the development of safer AF therapies, whether pharmacologic or nonpharmacologic, can potentially improve clinical outcomes.
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11
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Burashnikov A, Antzelevitch C. Advances in the Pharmacologic Management of Atrial Fibrillation. Card Electrophysiol Clin 2011; 3:157-167. [PMID: 21731596 PMCID: PMC3125069 DOI: 10.1016/j.ccep.2010.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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AZD1305 exerts atrial predominant electrophysiological actions and is effective in suppressing atrial fibrillation and preventing its reinduction in the dog. J Cardiovasc Pharmacol 2010; 56:80-90. [PMID: 20386458 DOI: 10.1097/fjc.0b013e3181e0bc6b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Recent development of drugs for the treatment of atrial fibrillation (AF) has focused on atrial selective agents. We examined the atrioventricular differences in sodium channel block of the antiarrhythmic agent AZD1305 in atria and ventricles of anesthetized dogs in vivo, canine isolated arterially perfused preparations in vitro, and isolated myocytes using whole-cell patch-clamp techniques. AZD1305 did not change heart rate or blood pressure in vivo but prolonged action potential duration and increased effective refractory period, diastolic threshold of excitation, and conduction time preferentially in atria both in vitro and in vivo. AZD1305 reduced the maximum rate of rise of the action potential upstroke (V(max)) predominantly in atria (-51% +/- 10% in atria vs. -31% +/- 23% in ventricles; 3 microM; cycle length = 500 milliseconds). Fast sodium current (I(Na)) was blocked by AZD1305 to a greater degree in atrial versus ventricular myocytes (particularly tonic inhibition). In coronary-perfused right atria, AZD1305 very effectively prevented induction of persistent acetylcholine-mediated AF and, in a different set of atria, terminated persistent AF (in 5 of 5 and 7 of 8 atria, respectively). In conclusion, AZD1305 exerts atrial predominant sodium channel-blocking effects in vitro and in vivo and effectively suppresses AF.
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13
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Ravens U. Antiarrhythmic therapy in atrial fibrillation. Pharmacol Ther 2010; 128:129-45. [DOI: 10.1016/j.pharmthera.2010.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 06/11/2010] [Indexed: 12/19/2022]
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Morrow JP, Reiffel JA. Chronic Maintenance of Sinus Rhythm in Patients with Atrial Fibrillation Using Antiarrhythmic Drugs: Update 2010. Card Electrophysiol Clin 2010; 2:409-418. [PMID: 28770799 DOI: 10.1016/j.ccep.2010.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Atrial fibrillation (AF) is a growing public health concern. For most patients the treatment of AF involves antiarrhythmic drugs. Despite the widespread use of antiarrhythmic drugs for the conversion of AF and maintenance of normal sinus rhythm, their use is limited by modest efficacy, frequent intolerance, and the potential for serious ventricular proarrhythmia and organ toxicity. Better medications are urgently needed. Optimizing the way current agents are used is vital in the interim. This article discusses such issues.
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Affiliation(s)
- John P Morrow
- Division of Cardiology, Department of Medicine, Columbia University Medical Center, New York, NY 10032, USA
| | - James A Reiffel
- Division of Cardiology, Department of Medicine, Columbia University Medical Center, New York, NY 10032, USA; 161 Fort Washington Avenue, Columbia University Medical Center, New York, NY 10032, USA
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A Randomized Invasive Cardiac Electrophysiology Study of the Combined Ion Channel Blocker AZD1305 in Patients After Catheter Ablation of Atrial Flutter. J Cardiovasc Pharmacol 2010; 56:300-8. [DOI: 10.1097/fjc.0b013e3181ed0859] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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16
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Diness JG, Sørensen US, Nissen JD, Al-Shahib B, Jespersen T, Grunnet M, Hansen RS. Inhibition of Small-Conductance Ca
2+
-Activated K
+
Channels Terminates and Protects Against Atrial Fibrillation. Circ Arrhythm Electrophysiol 2010; 3:380-90. [DOI: 10.1161/circep.110.957407] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Recently, evidence has emerged that small-conductance Ca
2+
-activated K
+
(SK) channels are predominantly expressed in the atria in a number of species including human. In rat, guinea pig, and rabbit ex vivo and in vivo models of atrial fibrillation (AF), we used 3 different SK channel inhibitors, UCL1684,
N
-(pyridin-2-yl)-4-(pyridin-2-yl)thiazol-2-amine (ICA), and NS8593, to assess the hypothesis that pharmacological inhibition of SK channels is antiarrhythmic.
Methods and Results—
In isolated, perfused guinea pig hearts, AF could be induced in all control hearts (n=7) with a combination of 1 μmol/L acetylcholine combined with electric stimulation. Pretreatment with 3 μmol/L NS8593, which had no effect on QT interval, prolonged the atrial effective refractory period by 37.1±7.7% (
P
<0.001) and prevented acetylcholine-induced AF (
P
<0.001, n=7). After AF induction, perfusion with NS8593 (10 μmol/L), UCL1684 (1 μmol/L), or ICA (1 μmol/L) terminated AF in all hearts, comparable to 10 μmol/L amiodarone. In isolated, perfused rat hearts, AF was induced with electric stimulation; 10 μmol/L NS8593 terminated AF and prevented reinduction of AF in all hearts (n=6,
P
<0.001). In all hearts, AF could be reinduced after washing. In isolated, perfused rabbit hearts, AF was induced with 10 μmol/L acetylcholine and burst pacing; 10 μmol/L NS8593 terminated AF and prevented reinduction of AF in all hearts (n=6,
P
<0.001). After washing, AF could be reinduced in 75% of the hearts (n=4,
P
=0.06). In an in vivo rat model of acute AF induced by burst pacing, injection of 5 mg/kg of either NS8593 or amiodarone shortened AF duration significantly to (23.2±20.0%,
P
<0.001, n=5, and 26.2±17.9%,
P
<0.001, n=5, respectively) as compared with injection of vehicle (96.3±33.2%, n=5).
Conclusions—
Inhibition of SK channels prolongs atrial effective refractory period without affecting QT interval and prevents and terminates AF ex vivo and in vivo, thus offering a promising new therapeutic opportunity in the treatment of AF.
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Affiliation(s)
- Jonas Goldin Diness
- From NeuroSearch A/S (J.G.D., U.S.S., B.A.-S., M.G., R.S.H.), Ballerup, Denmark; and the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.G.D., J.D.N., T.J., M.G.), Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ulrik S. Sørensen
- From NeuroSearch A/S (J.G.D., U.S.S., B.A.-S., M.G., R.S.H.), Ballerup, Denmark; and the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.G.D., J.D.N., T.J., M.G.), Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jakob Dahl Nissen
- From NeuroSearch A/S (J.G.D., U.S.S., B.A.-S., M.G., R.S.H.), Ballerup, Denmark; and the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.G.D., J.D.N., T.J., M.G.), Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Baha Al-Shahib
- From NeuroSearch A/S (J.G.D., U.S.S., B.A.-S., M.G., R.S.H.), Ballerup, Denmark; and the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.G.D., J.D.N., T.J., M.G.), Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- From NeuroSearch A/S (J.G.D., U.S.S., B.A.-S., M.G., R.S.H.), Ballerup, Denmark; and the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.G.D., J.D.N., T.J., M.G.), Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Grunnet
- From NeuroSearch A/S (J.G.D., U.S.S., B.A.-S., M.G., R.S.H.), Ballerup, Denmark; and the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.G.D., J.D.N., T.J., M.G.), Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rie Schultz Hansen
- From NeuroSearch A/S (J.G.D., U.S.S., B.A.-S., M.G., R.S.H.), Ballerup, Denmark; and the Danish National Research Foundation Centre for Cardiac Arrhythmia (J.G.D., J.D.N., T.J., M.G.), Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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Sicouri S, Carlsson L, Antzelevitch C. Electrophysiologic and antiarrhythmic effects of AZD1305 in canine pulmonary vein sleeves. J Pharmacol Exp Ther 2010; 334:255-9. [PMID: 20360353 PMCID: PMC2912040 DOI: 10.1124/jpet.110.166702] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The objective of this study was to examine the electrophysiologic and antiarrhythmic effects of the new antiarrhythmic agent tert-butyl (2-[7-[2-(4-cyano-2-fluorophenoxy)ethyl]-9-oxa-3,7-diazabicyclo[3.3.1]non3-yl]ethyl)carbamate (AZD1305) in canine pulmonary vein (PV) sleeve preparations isolated from untreated and long-term amiodarone-treated animals. Ectopic activity arising from PV sleeves plays a prominent role in the development of atrial fibrillation (AF). Delayed afterdepolarizations (DADs) and late phase 3 early afterdepolarizations (EADs), originating from the PV have been proposed as potential triggers in initiation of AF. Action potentials were recorded from canine superfused PV sleeves using standard microelectrode techniques. Acetylcholine (1 microM), isoproterenol (1 microM), or their combination was used to induce EADs, DADs, and triggered activity (TA). The effects of AZD1305 (0.1-10 microM) were evaluated in PV sleeve preparations isolated from untreated and amiodarone-treated (40 mg/kg daily for 6 weeks) dogs. AZD1305 (0.1-10 microM, 30 min) significantly prolonged action potential duration and reduced excitability. Abbreviating basic cycle length from 1000 to 300 ms resulted in a decrease of V(max) from 314 +/- 79 to 251 +/- 55 V/s (Delta = -20%) in control and from 177 +/- 53 to 76.5 +/- 33 V/s (Delta = -57%) after AZD1305 (n = 6, p < 0.05). AZD1305 markedly attenuated or suppressed DADs and DAD-induced TA, but not late phase 3 EADs. AZD1305-induced attenuation of excitability, leading to activation failure at much longer cycle lengths, was much more pronounced in PV from amiodarone-treated dogs. Potent effects of AZD1305 to depress excitability, prolong action potential duration, and suppress DAD-induced triggered activity in canine PV sleeve preparations may be effective in suppressing triggers responsible for the genesis of AF and other atrial arrhythmias.
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Affiliation(s)
- Serge Sicouri
- Masonic Medical Research Laboratory, Utica, NY 13501, USA.
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Abstract
Atrial fibrillation (AF) is a growing clinical problem associated with increased morbidity and mortality. Currently available antiarrhythmic drugs (AADs), although highly effective in acute cardioversion of paroxysmal AF, are generally only moderately successful in long-term maintenance of sinus rhythm. The use of AADs is often associated with an increased risk of ventricular proarrhythmia, extracardiac toxicity, and exacerbation of concomitant diseases such as heart failure. AF is commonly associated with intracardiac and extracardiac disease, which can modulate the efficacy and safety of AAD therapy. In light of the multifactorial intracardiac and extracardiac causes of AF generation, current development of anti-AF agents is focused on modulation of ion channel activity as well as on upstream therapies that reduce structural substrates. The available data indicate that multiple ion channel blockers exhibiting potent inhibition of peak I(Na) with relatively rapid unbinding kinetics, as well as inhibition of late I(Na) and I(Kr), may be preferable for the management of AF when considering both safety and efficacy.
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Jacobson I, Carlsson L, Duker G. Beat-by-beat QT interval variability, but not QT prolongation per se, predicts drug-induced torsades de pointes in the anaesthetised methoxamine-sensitized rabbit. J Pharmacol Toxicol Methods 2010; 63:40-6. [PMID: 20451633 DOI: 10.1016/j.vascn.2010.04.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2010] [Revised: 04/19/2010] [Accepted: 04/23/2010] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Accumulating evidence suggest that drug-induced QT prolongation per se poorly predicts repolarisation-related proarrhythmia liability. We examined whether beat-by-beat variability of the QT interval may be a complementary proarrhythmia marker to QT prolongation. METHODS Anaesthetised rabbits sensitized towards developing torsades de pointes (TdP) were infused for 30 min maximum with explorative antiarrhythmic compounds characterised as mixed ion channel blockers. Based on the outcome in this model the compounds were classified as having a low (TdPlow; n=5), intermediate (TdPintermediate; n=7) or high (TdPhigh; n=10) proarrhythmic potential. Dofetilide (n=4) was included as a representative of a selective IKr-blocking antiarrhythmic with known high proarrhythmic potential. QT interval prolongation and beat-by-beat QT variability (quantified as the short-term variability, STV) were continuously assessed during the infusion or up to the point where ventricular proarrhythmias were induced. RESULTS All compounds significantly prolonged the QT interval. For TdPlow and TdPhigh compounds the QT interval maximally increased from 169 ± 14 to 225 ± 28 ms (p<0.05) and from 186 ± 21 to 268 ± 42 ms (p<0.01), respectively. Likewise, in the dofetilide-infused rabbits the QT interval maximally increased from 177 ± 11 to 243 ± 25 ms (p<0.01). In contrast, whereas the STV in rabbits administered the TdPhigh compounds or dofetilide significantly increased prior to proarrhythmia induction (from 1.6 ± 0.4 to 10.5 ± 5.6 ms and from 1.6 ± 0.5 to 5.9 ± 1.8 ms, p<0.01) it remained unaltered in the TdPlow group (1.3 ± 0.6 to 2.2 ± 0.9 ms). In the TdPintermediate group, rabbits experiencing TdP had a similar maximal QT prolongation as the non-susceptible rabbits whereas the change in the STV was significantly different (from 0.9 ± 0.5 to 8.7 ± 7.3 ms vs 0.8 ± 0.3 to 2.5 ± 1.1 ms). DISCUSSION It is concluded from the present series of experiments in a sensitive rabbit model of TdP that increased beat-by-beat QT interval variability precedes drug-induced TdP. In addition, assessment of this potential proarrhythmia marker may be useful in discriminating highly proarrhythmic compounds from compounds with a low proarrhythmic potential.
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Tjäderborn M, Aunes-Jansson M, Samuelsson E, Frison L, Johansson S, Berggren A, Edvardsson N. Prediction of drug-related morphological changes of the T wave. SCAND CARDIOVASC J 2010; 44:215-22. [PMID: 20429697 DOI: 10.3109/14017431003789892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES To describe the characteristics of patients presenting with morphological T wave changes that lead to measurement difficulties, and to identify possible predictors of such changes at baseline and early after start of treatment. DESIGN ECGs from 145 patients receiving a combined potassium and sodium channel blocking agent for conversion of atrial fibrillation (AF), underwent semiautomatic analysis in a digitalized high-precision analysis program. In 15 patients, one or more ECGs were identified as difficult to interpret due to morphological T wave changes. They were compared with the 130 patients without such changes. RESULTS A history of cardiac failure (p=0.027), a smaller left atrial area (p=0.010) and a longer QT(tang) minus QT(top) interval (p<0.001) at baseline was significantly more frequent as compared to the controls. Identified patients also had somewhat longer baseline QT interval duration (median QT(cB) 432 vs. 408 ms, N.S.) and a larger proportion of them were females (47% vs. 27%, N.S.). After start of infusion the QT(cB) became significantly longer in identified patients than in controls (p=0.012). CONCLUSIONS Independent predictors of subsequent morphological changes were found at baseline and shortly after start of treatment, and may be of use to identify individuals with a reduced repolarization reserve.
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Burashnikov A, Antzelevitch C. Atrial-selective sodium channel block for the treatment of atrial fibrillation. Expert Opin Emerg Drugs 2009; 14:233-49. [PMID: 19466903 DOI: 10.1517/14728210902997939] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The pharmacological approach to therapy of atrial fibrillation (AF) is often associated with adverse effects resulting in the development of ventricular arrhythmias. As a consequence, much of the focus in recent years has been on development of atrial-selective agents. Atrial-selective sodium channel blockers have recently been shown to exist and be useful in the management of AF. This review summarizes the available data relative to current therapies, focusing on our understanding of the actions of atrial selective sodium channel blockers in suppressing and preventing the induction of AF and electrophysiological properties that confer atrial-selectivity to these antifibrillatory drugs.
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Affiliation(s)
- Alexander Burashnikov
- Research Scientist Masonic Medical Research Laboratory, 2150 Bleecker Street, Utica, NY 13501, USA
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Assessment of the Ion Channel-blocking Profile of the Novel Combined Ion Channel Blocker AZD1305 and Its Proarrhythmic Potential Versus Dofetilide in the Methoxamine-sensitized Rabbit In Vivo. J Cardiovasc Pharmacol 2009; 54:82-9. [DOI: 10.1097/fjc.0b013e3181ac62c9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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