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Norup Hertel J, Isaksen JL, Jerltorp K, Dalgas Nissen S, Hansen M, Saljic A, Linz B, Sattler S, Ye C, Overgaard Larsen J, Nørregaard M, Chaldoupi SM, Gang U, Manninger M, Jespersen T, Linz D. Catheter-based pulmonary vein isolation fails to prevent transient atrial arrhythmogenic changes related to acute obstructive respiratory events in a porcine model. Europace 2024; 26:euae132. [PMID: 38758963 PMCID: PMC11167663 DOI: 10.1093/europace/euae132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/07/2024] [Indexed: 05/19/2024] Open
Abstract
AIMS Pulmonary vein isolation (PVI) is the corner stone of modern rhythm control strategies in patients with atrial fibrillation (AF). Sleep-disordered breathing (SDB) is prevalent in more than 50% of patients undergoing AF ablation, and studies have indicated a greater recurrence rate after PVI in patients with SDB. Herein, we study the effect of catheter-based PVI on AF in a pig model for SDB. METHODS AND RESULTS In 11 sedated spontaneously breathing pigs, obstructive apnoeas were simulated by 75 s of intermittent negative upper airway pressure (INAP) applied by a negative pressure device connected to the endotracheal tube. Intermittent negative upper airway pressures were performed before and after PVI. AF-inducibility and atrial effective refractory periods (aERPs) were determined before and during INAP by programmed atrial stimulation. Pulmonary vein isolation prolonged the aERP by 48 ± 27 ms in the right atrium (RA) (P < 0.0001) and by 40 ± 34 ms in the left atrium (LA) (P = 0.0004). Following PVI, AF-inducibility dropped from 28 ± 26% to 0% (P = 0.0009). Intermittent negative upper airway pressure was associated with a transient aERP-shortening (ΔaERP) in both atria, which was not prevented by PVI (INAP indued ΔaERP after PVI in the RA: -57 ± 34 ms, P = 0.0002; in the LA: -42 ± 24 ms, P < 0.0001). Intermittent negative upper airway pressure was associated with a transient increase in AF-inducibility (from 28 ± 26% to 69 ± 21%; P = 0.0008), which was not attenuated by PVI [INAP-associated AF-inducibility after PVI: 58 ± 33% (P = 0.5)]. CONCLUSION Transient atrial arrhythmogenic changes related to acute obstructive respiratory events are not prevented by electrical isolation of the pulmonary veins, which partially explains the increased AF recurrence in patients with SDB after PVI procedures.
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Affiliation(s)
- Julie Norup Hertel
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Jonas L Isaksen
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Kezia Jerltorp
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Sarah Dalgas Nissen
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Malthe Hansen
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Arnela Saljic
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- West German Heart and Vascular Center, Institute of Pharmacology, University Duisburg-Essen, Germany
| | - Benedikt Linz
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Stefan Sattler
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Charles Ye
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Jakob Overgaard Larsen
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Malene Nørregaard
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Sevasti-Maria Chaldoupi
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Uffe Gang
- Department of Cardiology, Zealand University Hospital Roskilde, Roskilde, Denmark
| | - Martin Manninger
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Centre, Maastricht, The Netherlands
- Division of Cardiology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Thomas Jespersen
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Dominik Linz
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Centre, Maastricht, The Netherlands
- Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, Royal Adelaide Hospital, University of Adelaide, Australia
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Norup Hertel J, Linz B, Isaksen J, Jerltorp K, Leonhardt C, Gottlieb L, Saljic A, Jespersen T, Linz D. Inhibition of the acetylcholine-regulated potassium current prevents transient apnea-related atrial arrhythmogenic changes in a porcine model. Heart Rhythm 2024; 21:622-629. [PMID: 38280622 DOI: 10.1016/j.hrthm.2024.01.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 01/29/2024]
Abstract
BACKGROUND More than 50% of patients with atrial fibrillation (AF) suffer from sleep disordered breathing (SDB). Obstructive respiratory events contribute to a transient, vagally mediated atrial arrhythmogenic substrate, which is resistant to most available antiarrhythmic drugs. OBJECTIVE The purpose of this study was to investigate the effect of pharmacologic inhibition of the G-protein-gated acetylcholine-regulated potassium current (IK,ACh) with and without acute autonomic nervous system activation by nicotine in a pig model for obstructive respiratory events. METHODS In 21 pigs, SDB was simulated by applying an intermittent negative upper airway pressure (INAP). AF inducibility and atrial effective refractory periods (aERPs) were determined before and during INAP by an S1S2 atrial pacing-protocol. Pigs were randomized into 3 groups-group 1: vehicle (n = 4); group 2: XAF-1407 (IK,ACh inhibitor) (n = 7); and group 3: nicotine followed by XAF-1407 (n = 10). RESULTS In group 1, INAP shortened aERP (ΔaERP -42.6 ms; P = .004) and transiently increased AF inducibility from 0% to 31%. In group 2, XAF-1407 prolonged aERP by 25.2 ms (P = .005) during normal breathing and prevented INAP-induced aERP shortening (ΔaERP -3.6 ms; P = .3) and AF inducibility. In group 3, INAP transiently shortened aERP during nicotine perfusion (ΔaERP -33.6 ms; P = .004) and increased AF inducibility up to 61%, which both were prevented by XAF-1407. CONCLUSION Simulated obstructive respiratory events transiently shorten aERP and increase AF inducibility, which can be prevented by the IK,ACh-inhibitor XAF-1407. XAF-1407 also prevents these arrhythmogenic changes induced by obstructive respiratory events during nicotine perfusion. Whether IK,ACh channels represent a target for SDB-related AF in humans warrants further study.
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Affiliation(s)
- Julie Norup Hertel
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Benedikt Linz
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonas Isaksen
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kezia Jerltorp
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Caroline Leonhardt
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lisa Gottlieb
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arnela Saljic
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dominik Linz
- Faculty of Health and Medical Sciences, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; Centre for Heart Rhythm Disorders, South Australian Health and Medical Research Institute, Royal Adelaide Hospital, University of Adelaide, Australia; Department of Cardiology, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands.
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Van NTH, Kim WK, Nam JH. Challenges in the Therapeutic Targeting of KCa Channels: From Basic Physiology to Clinical Applications. Int J Mol Sci 2024; 25:2965. [PMID: 38474212 PMCID: PMC10932353 DOI: 10.3390/ijms25052965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 03/14/2024] Open
Abstract
Calcium-activated potassium (KCa) channels are ubiquitously expressed throughout the body and are able to regulate membrane potential and intracellular calcium concentrations, thereby playing key roles in cellular physiology and signal transmission. Consequently, it is unsurprising that KCa channels have been implicated in various diseases, making them potential targets for pharmaceutical interventions. Over the past two decades, numerous studies have been conducted to develop KCa channel-targeting drugs, including those for disorders of the central and peripheral nervous, cardiovascular, and urinary systems and for cancer. In this review, we synthesize recent findings regarding the structure and activating mechanisms of KCa channels. We also discuss the role of KCa channel modulators in therapeutic medicine. Finally, we identify the major reasons behind the delay in bringing these modulators to the pharmaceutical market and propose new strategies to promote their application.
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Affiliation(s)
- Nhung Thi Hong Van
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
| | - Woo Kyung Kim
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
- Department of Internal Medicine, Graduate School of Medicine, Dongguk University, Goyang 10326, Republic of Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea;
- Channelopathy Research Center (CRC), Dongguk University College of Medicine, Goyang 10326, Republic of Korea
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Herrera NT, Zhang X, Ni H, Maleckar MM, Heijman J, Dobrev D, Grandi E, Morotti S. Dual effects of the small-conductance Ca 2+-activated K + current on human atrial electrophysiology and Ca 2+-driven arrhythmogenesis: an in silico study. Am J Physiol Heart Circ Physiol 2023; 325:H896-H908. [PMID: 37624096 PMCID: PMC10659325 DOI: 10.1152/ajpheart.00362.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/11/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023]
Abstract
By sensing changes in intracellular Ca2+, small-conductance Ca2+-activated K+ (SK) channels dynamically regulate the dynamics of the cardiac action potential (AP) on a beat-to-beat basis. Given their predominance in atria versus ventricles, SK channels are considered a promising atrial-selective pharmacological target against atrial fibrillation (AF), the most common cardiac arrhythmia. However, the precise contribution of SK current (ISK) to atrial arrhythmogenesis is poorly understood, and may potentially involve different mechanisms that depend on species, heart rates, and degree of AF-induced atrial remodeling. Both reduced and enhanced ISK have been linked to AF. Similarly, both SK channel up- and downregulation have been reported in chronic AF (cAF) versus normal sinus rhythm (nSR) patient samples. Here, we use our multiscale modeling framework to obtain mechanistic insights into the contribution of ISK in human atrial cardiomyocyte electrophysiology. We simulate several protocols to quantify how ISK modulation affects the regulation of AP duration (APD), Ca2+ transient, refractoriness, and occurrence of alternans and delayed afterdepolarizations (DADs). Our simulations show that ISK activation shortens the APD and atrial effective refractory period, limits Ca2+ cycling, and slightly increases the propensity for alternans in both nSR and cAF conditions. We also show that increasing ISK counteracts DAD development by enhancing the repolarization force that opposes the Ca2+-dependent depolarization. Taken together, our results suggest that increasing ISK in human atrial cardiomyocytes could promote reentry while protecting against triggered activity. Depending on the leading arrhythmogenic mechanism, ISK inhibition may thus be a beneficial or detrimental anti-AF strategy.NEW & NOTEWORTHY Using our established framework for human atrial myocyte simulations, we investigated the role of the small-conductance Ca2+-activated K+ current (ISK) in the regulation of cell function and the development of Ca2+-driven arrhythmias. We found that ISK inhibition, a promising atrial-selective pharmacological strategy against atrial fibrillation, counteracts the reentry-promoting abbreviation of atrial refractoriness, but renders human atrial myocytes more vulnerable to delayed afterdepolarizations, thus potentially increasing the propensity for ectopic (triggered) activity.
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Affiliation(s)
- Nathaniel T Herrera
- Department of Pharmacology, University of California Davis, Davis, California, United States
| | - Xianwei Zhang
- Department of Pharmacology, University of California Davis, Davis, California, United States
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, California, United States
| | - Mary M Maleckar
- Department of Computational Physiology, Simula Research Laboratory, Oslo, Norway
| | - Jordi Heijman
- Department of Cardiology, Faculty of Health, Medicine, and Life Sciences, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Dobromir Dobrev
- Faculty of Medicine, West German Heart and Vascular Center, Institute of Pharmacology, University Duisburg-Essen, Essen, Germany
- Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada
- Department of Integrative Physiology, Baylor College of Medicine, Houston, Texas, United States
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, California, United States
| | - Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, California, United States
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Saljic A, Heijman J, Dobrev D. Recent Advances in Antiarrhythmic Drug Therapy. Drugs 2023; 83:1147-1160. [PMID: 37540446 PMCID: PMC10462572 DOI: 10.1007/s40265-023-01923-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2023] [Indexed: 08/05/2023]
Abstract
Cardiac arrhythmias remain a common cause of death and disability. Antiarrhythmic drugs (AADs) and antiarrhythmic agents remain a cornerstone of current cardiac arrhythmia management, despite moderate efficacy and the potential for significant adverse proarrhythmic effects. Due to conceptual, regulatory and financial considerations, the number of novel antiarrhythmic targets and agents in the development pipeline has decreased substantially during the last few decades. However, several promising candidates remain and there are exciting developments in repurposing and reformulating already existing drugs for indications related to cardiac arrhythmias. This review discusses the key conceptual considerations for the development of new antiarrhythmic agents, summarizes new compounds and formulations currently in clinical development for rhythm control of atrial fibrillation, and highlights the potential for drug repurposing. Finally, future directions in AAD development are discussed. Together with an ever-increasing understanding of the molecular mechanisms underlying cardiac arrhythmias, these components support a cautiously optimistic outlook towards improved pharmacological treatment opportunities for patients suffering from cardiac arrhythmias.
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Affiliation(s)
- Arnela Saljic
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Jordi Heijman
- Department of Cardiology, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands
| | - Dobromir Dobrev
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
- Montréal Heart Institute and University de Montréal, Medicine and Research Center, Montréal, Canada.
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, USA.
- , Hufelandstrasse 55, 45122, Essen, Germany.
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