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Nagase S, Kataoka N, Morita H, Kamakura T, Ueoka A, Nakamura T, Oka S, Miyazaki Y, Wakamiya A, Nakajima K, Ueda N, Wada M, Ishibashi K, Inoue Y, Miyamoto K, Aiba T, Kusano K. Demonstration of Arrhythmia Substrate-Associated Dispersion of Repolarization by Epicardial Unipolar Mapping in Brugada Syndrome. JACC Clin Electrophysiol 2024; 10:1576-1588. [PMID: 38864810 DOI: 10.1016/j.jacep.2024.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 06/13/2024]
Abstract
BACKGROUND Epicardial unipolar mapping has not been thoroughly investigated in Brugada syndrome (BrS). OBJECTIVES This study aims to examine the characteristics of epicardial unipolar potentials in BrS and investigate the differences from overt cardiomyopathy. METHODS Epicardial mapping was performed in 8 patients with BrS and 6 patients with cardiomyopathy. We investigated the J-wave amplitudes using unipolar recordings at delayed potential (DP) sites via bipolar recordings. The repolarization time (RT) at and around the DP recording sites was measured, and maximum dispersion of the RT divided by the distance was defined as the RT dispersion index. RESULTS Epicardial mapping at baseline revealed significantly higher J-wave amplitude with bipolar DP in patients with BrS than in patients with cardiomyopathy. J-wave amplitude ≥0.42 mV had 99.1% sensitivity and 100% specificity for diagnosing BrS. The RT dispersion index was significantly higher in patients with BrS than in patients with cardiomyopathy at baseline. In all patients with BrS, coved-type unipolar electrograms without negative T waves (short RT) appeared close to coved-type electrograms with negative T waves (long RT) at the DP recording sites after pilsicainide administration. Thus, a steep RT dispersion was observed in this region, and ventricular arrhythmias emerged from this shorter RT area in all 3 patients with BrS in whom ventricular arrhythmias were induced. CONCLUSIONS Bipolar DP-related prominent unipolar J waves and steep repolarization gradients may be more specific for characterizing BrS than for overt cardiomyopathy. Ventricular arrhythmias in BrS are associated with a steep repolarization gradient, indicating phase 2 re-entry as a possible cause.
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Affiliation(s)
- Satoshi Nagase
- Department of Advanced Arrhythmia and Translational Medical Science, National Cerebral and Cardiovascular Center, Suita, Japan.
| | - Naoya Kataoka
- Second Department of Internal Medicine, University of Toyama, Toyama, Japan
| | - Hiroshi Morita
- Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Tsukasa Kamakura
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Akira Ueoka
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan
| | - Toshihiro Nakamura
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Satoshi Oka
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Yuichiro Miyazaki
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Akinori Wakamiya
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Kenzaburo Nakajima
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Nobuhiko Ueda
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Mitsuru Wada
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Kohei Ishibashi
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Yuko Inoue
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Koji Miyamoto
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Takeshi Aiba
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Kengo Kusano
- Division of Arrhythmia, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
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Renard E, Surget E, Walton RD, Michel C, Benoist D, Dubes V, Guillot B, Martinez ME, Hocini M, Haïssaguerre M, Bernus O. Distinct Electrogram Features and Ventricular Arrhythmia Induction Modes Between Repolarization and Conduction Heterogeneities. JACC Clin Electrophysiol 2024; 10:1424-1438. [PMID: 38661605 DOI: 10.1016/j.jacep.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 04/26/2024]
Abstract
BACKGROUND Recent clinical studies have indicated the presence of localized electrical abnormalities in idiopathic ventricular fibrillation and J-wave syndrome patients. OBJECTIVES This study aims to characterize the specific electrical signatures of localized repolarization and conduction heterogeneities and their respective role in vulnerability to arrhythmias. METHODS Optical mapping was performed in porcine right ventricles with local: 1) repolarization shortening; 2) conduction slowing; or 3) structural heterogeneity induced by locally perfusing: 1) pinacidil (20 μmol/L, n = 13); or 2) flecainide (2 μmol/L, n = 13) via an epicardial catheter; or 3) by local epicardial tissue destruction (9 radiofrequency lesions n = 12). Electrograms were recorded (n = 5 in each group) and spontaneous and induced arrhythmias were quantified and optically mapped. RESULTS Electrograms were normal in (1) but showed local fragmentation in 40% of preparations in (2) with greater effects observed at high pacing frequencies dependent on the wavefront direction. In (3), the structural substrate alone increased the width and number of peaks in the electrograms, and addition of flecainide induced pronounced fragmentation (≥3 peaks and ≥70 ms) in all cases. Occurrence of spontaneous arrhythmias was significantly increased in (1) and (2) (P < 0.0001 and 0.05, respectively, vs baseline) and were triggered by ectopies. Vulnerability to arrhythmias at high pacing frequencies (≥2 Hz) was the lowest in (1) and greatest in (2). CONCLUSIONS Microstructural substrates have the most pronounced impact on electrograms, especially when combined with sodium channel blockers, whereas local action potential duration shortening does not lead to electrogram fragmentation even though it is associated with the highest prevalence of spontaneous arrhythmias.
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Affiliation(s)
- Estelle Renard
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.
| | - Elodie Surget
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Richard D Walton
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Cindy Michel
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - David Benoist
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Virginie Dubes
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Bastien Guillot
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Marine E Martinez
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Mélèze Hocini
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France; CHU de Bordeaux, Département d'électrophysiologie et de stimulation cardiaques, Hôpital Cardiologique du Haut-Lévêque, Pessac, France
| | - Michel Haïssaguerre
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France; CHU de Bordeaux, Département d'électrophysiologie et de stimulation cardiaques, Hôpital Cardiologique du Haut-Lévêque, Pessac, France
| | - Olivier Bernus
- IHU LIRYC, L'Institut des maladies du RYthme Cardiaque, Fondation Bordeaux Université, Bordeaux, France; University of Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
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Theisen B, Holtz A, Rajagopalan V. Noncoding RNAs and Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes in Cardiac Arrhythmic Brugada Syndrome. Cells 2023; 12:2398. [PMID: 37830612 PMCID: PMC10571919 DOI: 10.3390/cells12192398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 09/21/2023] [Accepted: 09/22/2023] [Indexed: 10/14/2023] Open
Abstract
Hundreds of thousands of people die each year as a result of sudden cardiac death, and many are due to heart rhythm disorders. One of the major causes of these arrhythmic events is Brugada syndrome, a cardiac channelopathy that results in abnormal cardiac conduction, severe life-threatening arrhythmias, and, on many occasions, death. This disorder has been associated with mutations and dysfunction of about two dozen genes; however, the majority of the patients do not have a definite cause for the diagnosis of Brugada Syndrome. The protein-coding genes represent only a very small fraction of the mammalian genome, and the majority of the noncoding regions of the genome are actively transcribed. Studies have shown that most of the loci associated with electrophysiological traits are located in noncoding regulatory regions and are expected to affect gene expression dosage and cardiac ion channel function. Noncoding RNAs serve an expanding number of regulatory and other functional roles within the cells, including but not limited to transcriptional, post-transcriptional, and epigenetic regulation. The major noncoding RNAs found in Brugada Syndrome include microRNAs; however, others such as long noncoding RNAs are also identified. They contribute to pathogenesis by interacting with ion channels and/or are detectable as clinical biomarkers. Stem cells have received significant attention in the recent past, and can be differentiated into many different cell types including those in the heart. In addition to contractile and relaxational properties, BrS-relevant electrophysiological phenotypes are also demonstrated in cardiomyocytes differentiated from stem cells induced from adult human cells. In this review, we discuss the current understanding of noncoding regions of the genome and their RNA biology in Brugada Syndrome. We also delve into the role of stem cells, especially human induced pluripotent stem cell-derived cardiac differentiated cells, in the investigation of Brugada syndrome in preclinical and clinical studies.
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Affiliation(s)
- Benjamin Theisen
- Department of Biomedical and Anatomical Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR 72401, USA
| | - Austin Holtz
- Department of Biomedical and Anatomical Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR 72401, USA
| | - Viswanathan Rajagopalan
- Department of Biomedical and Anatomical Sciences, New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, Jonesboro, AR 72401, USA
- Arkansas Biosciences Institute, Jonesboro, AR 72401, USA
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4
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Kataoka N, Nagase S, Imamura T, Kinugawa K. Dynamics of unipolar J-ST elevation coupled to bipolar delayed potentials on the epicardium in Brugada syndrome: a case report. Eur Heart J Case Rep 2023; 7:ytad377. [PMID: 37575530 PMCID: PMC10415855 DOI: 10.1093/ehjcr/ytad377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 07/21/2023] [Accepted: 07/31/2023] [Indexed: 08/15/2023]
Abstract
Background The area of abnormal bipolar potentials in the right ventricular epicardium is recognized as an arrhythmogenic substrate in patients with Brugada syndrome (BrS); however, the correlation between local potentials and Brugada-type surface electrocardiograms (ECGs) remains unclear. Case summary A 49-year-old man with BrS who was hospitalized for refractory ventricular fibrillation underwent an electrocardiographic study with unipolar electrodes with the same bandwidth as surface ECGs. The right ventricular outflow tract epicardium showed abnormal bipolar potentials composed of split sharp and delayed dull components with coved-type J-ST elevation in the unipolar electrodes. The additional stimuli from the atrium gradually decreased the number of unipolar electrodes showing coved-type J-ST elevation along with a shortening of the local bipolar activation time. The pilsicainide provocation test induced a change in unipolar morphology from coved type to convex type and an intermittent local block of the divided and sharp components in bipolar electrodes. Of note, the unipolar J-ST elevation was not changed along with the localized conduction block in bipolar leads. Discussion The unipolar electrode waveforms during sinus rhythm change together with bipolar electrodes, consisting of sharp and blunt components in BrS. However, the convex-type J-ST elevation in unipolar leads persisted irrespective of the local conduction block in bipolar leads after pilsicainide provocation. These findings suggest the complexity of BrS mechanisms.
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Affiliation(s)
- Naoya Kataoka
- Second Department of Internal Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Satoshi Nagase
- Division of Arrhythmia and Electrophysiology, Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Teruhiko Imamura
- Second Department of Internal Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Koichiro Kinugawa
- Second Department of Internal Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
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5
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Renard E, Walton RD, Benoist D, Brette F, Bru-Mercier G, Chaigne S, Charron S, Constantin M, Douard M, Dubes V, Guillot B, Hof T, Magat J, Martinez ME, Michel C, Pallares-Lupon N, Pasdois P, Récalde A, Vaillant F, Sacher F, Labrousse L, Rogier J, Kyndt F, Baudic M, Schott JJ, Barc J, Probst V, Sarlandie M, Marionneau C, Ashton JL, Hocini M, Haïssaguerre M, Bernus O. Functional Epicardial Conduction Disturbances Due to a SCN5A Variant Associated With Brugada Syndrome. JACC Clin Electrophysiol 2023; 9:1248-1261. [PMID: 37227351 PMCID: PMC10406612 DOI: 10.1016/j.jacep.2023.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 03/06/2023] [Accepted: 03/10/2023] [Indexed: 05/26/2023]
Abstract
BACKGROUND Brugada syndrome is a significant cause of sudden cardiac death (SCD), but the underlying mechanisms remain hypothetical. OBJECTIVES This study aimed to elucidate this knowledge gap through detailed ex vivo human heart studies. METHODS A heart was obtained from a 15-year-old adolescent boy with normal electrocardiogram who experienced SCD. Postmortem genotyping was performed, and clinical examinations were done on first-degree relatives. The right ventricle was optically mapped, followed by high-field magnetic resonance imaging and histology. Connexin-43 and NaV1.5 were localized by immunofluorescence, and RNA and protein expression levels were studied. HEK-293 cell surface biotinylation assays were performed to examine NaV1.5 trafficking. RESULTS A Brugada-related SCD diagnosis was established for the donor because of a SCN5A Brugada-related variant (p.D356N) inherited from his mother, together with a concomitant NKX2.5 variant of unknown significance. Optical mapping demonstrated a localized epicardial region of impaired conduction near the outflow tract, in the absence of repolarization alterations and microstructural defects, leading to conduction blocks and figure-of-8 patterns. NaV1.5 and connexin-43 localizations were normal in this region, consistent with the finding that the p.D356N variant does not affect the trafficking, nor the expression of NaV1.5. Trends of decreased NaV1.5, connexin-43, and desmoglein-2 protein levels were noted; however, the RT-qPCR results suggested that the NKX2-5 variant was unlikely to be involved. CONCLUSIONS This study demonstrates for the first time that SCD associated with a Brugada-SCN5A variant can be caused by localized functionally, not structurally, impaired conduction.
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Affiliation(s)
- Estelle Renard
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France.
| | - Richard D Walton
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - David Benoist
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Fabien Brette
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Gilles Bru-Mercier
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Sébastien Chaigne
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Sabine Charron
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Marion Constantin
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Matthieu Douard
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Virginie Dubes
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Bastien Guillot
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Thomas Hof
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Julie Magat
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Marine E Martinez
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Cindy Michel
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Néstor Pallares-Lupon
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Philippe Pasdois
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Alice Récalde
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Fanny Vaillant
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
| | - Frédéric Sacher
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France; Centre Hospitalier Universitaire de Bordeaux, Département d'électrophysiologie et de stimulation cardiaques, Hôpital Cardiologique du Haut-Lévêque, Pessac, France
| | - Louis Labrousse
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Centre Hospitalier Universitaire de Bordeaux, Département de chirurgie cardiovasculaire, Hôpital Cardiologique du Haut-Lévêque, Pessac, France
| | - Julien Rogier
- Centre Hospitalier Universitaire de Bordeaux, Coordination des prélèvements d'organes et de tissus, Bordeaux, France
| | - Florence Kyndt
- Nantes Université, Centre Hospitalier Universitaire Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France; Centre Hospitalier Universitaire Nantes, Service de génétique médicale, Nantes, France
| | - Manon Baudic
- L'Institut du thorax, INSERM, CNRS, Université Nantes, Nantes, France
| | - Jean-Jacques Schott
- Nantes Université, Centre Hospitalier Universitaire Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Julien Barc
- Nantes Université, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Vincent Probst
- Nantes Université, Centre Hospitalier Universitaire Nantes, CNRS, INSERM, l'institut du thorax, Nantes, France
| | - Marine Sarlandie
- L'Institut du thorax, INSERM, CNRS, Université Nantes, Nantes, France
| | - Céline Marionneau
- L'Institut du thorax, INSERM, CNRS, Université Nantes, Nantes, France
| | - Jesse L Ashton
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Mélèze Hocini
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France; Centre Hospitalier Universitaire de Bordeaux, Département d'électrophysiologie et de stimulation cardiaques, Hôpital Cardiologique du Haut-Lévêque, Pessac, France
| | - Michel Haïssaguerre
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France; Centre Hospitalier Universitaire de Bordeaux, Département d'électrophysiologie et de stimulation cardiaques, Hôpital Cardiologique du Haut-Lévêque, Pessac, France
| | - Olivier Bernus
- IHU LIRYC, L'Institut de Rythmologie et Modélisation Cardiaque, Fondation Bordeaux Université, Bordeaux, France; Université Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Bordeaux, France
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6
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Miles C, Boukens BJ, Scrocco C, Wilde AA, Nademanee K, Haissaguerre M, Coronel R, Behr ER. Subepicardial Cardiomyopathy: A Disease Underlying J-Wave Syndromes and Idiopathic Ventricular Fibrillation. Circulation 2023; 147:1622-1633. [PMID: 37216437 PMCID: PMC11073566 DOI: 10.1161/circulationaha.122.061924] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 03/27/2023] [Indexed: 05/24/2023]
Abstract
Brugada syndrome (BrS), early repolarization syndrome (ERS), and idiopathic ventricular fibrillation (iVF) have long been considered primary electrical disorders associated with malignant ventricular arrhythmia and sudden cardiac death. However, recent studies have revealed the presence of subtle microstructural abnormalities of the extracellular matrix in some cases of BrS, ERS, and iVF, particularly within right ventricular subepicardial myocardium. Substrate-based ablation within this region has been shown to ameliorate the electrocardiographic phenotype and to reduce arrhythmia frequency in BrS. Patients with ERS and iVF may also exhibit low-voltage and fractionated electrograms in the ventricular subepicardial myocardium, which can be treated with ablation. A significant proportion of patients with BrS and ERS, as well as some iVF survivors, harbor pathogenic variants in the voltage-gated sodium channel gene, SCN5A, but the majority of genetic susceptibility of these disorders is likely to be polygenic. Here, we postulate that BrS, ERS, and iVF may form part of a spectrum of subtle subepicardial cardiomyopathy. We propose that impaired sodium current, along with genetic and environmental susceptibility, precipitates a reduction in epicardial conduction reserve, facilitating current-to-load mismatch at sites of structural discontinuity, giving rise to electrocardiographic changes and the arrhythmogenic substrate.
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Affiliation(s)
- Chris Miles
- Cardiovascular Clinical Academic Group, St. George’s University Hospitals’ NHS Foundation Trust and Molecular and Clinical Sciences Institute, St. George’s, University of London, UK (C.M., C.S., E.R.B.)
| | - Bastiaan J. Boukens
- Department of Medical Biology, University of Amsterdam, the Netherlands (B.J.B.)
- University of Maastricht, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, the Netherlands (B.J.B.)
| | - Chiara Scrocco
- Cardiovascular Clinical Academic Group, St. George’s University Hospitals’ NHS Foundation Trust and Molecular and Clinical Sciences Institute, St. George’s, University of London, UK (C.M., C.S., E.R.B.)
| | - Arthur A.M. Wilde
- Amsterdam UMC, University of Amsterdam, Department of Cardiology, the Netherlands (A.A.M.W.)
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, the Netherlands (A.A.M.W.)
- European Reference Network for rare, low-prevalence, and complex diseases of the heart: ERN GUARD-Heart (A.A.M.W., M.H.)
| | - Koonlawee Nademanee
- Center of Excellence in Arrhythmia Research Chulalongkorn University, Department of Medicine, Chulalongkorn University, Thailand (K.N.)
- Pacific Rim Electrophysiology Research Institute, Bumrungrad Hospital, Bangkok, Thailand (K.N.)
| | - Michel Haissaguerre
- European Reference Network for rare, low-prevalence, and complex diseases of the heart: ERN GUARD-Heart (A.A.M.W., M.H.)
- Institut Hospitalo-Universitaire Liryc, Electrophysiology and Heart Modeling Institute, Pessac, France (M.H.)
- Department of Electrophysiology and Cardiac Stimulation, Centre Hospitalier Universitaire de Bordeaux, France (M.H.)
| | - Ruben Coronel
- Department of Experimental Cardiology, Amsterdam University Medical Centers, Cardiovascular Science, the Netherlands (R.C.)
| | - Elijah R. Behr
- Cardiovascular Clinical Academic Group, St. George’s University Hospitals’ NHS Foundation Trust and Molecular and Clinical Sciences Institute, St. George’s, University of London, UK (C.M., C.S., E.R.B.)
- Mayo Clinic Healthcare, London, UK (E.R.B.)
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7
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Morimoto Y, Morita H, Ejiri K, Mizuno T, Masuda T, Ueoka A, Asada S, Miyamoto M, Kawada S, Nakagawa K, Nishii N, Nakamura K, Ito H. Significant Delayed Activation on the Right Ventricular Outflow Tract Represents Complete Right Bundle-Branch Block Pattern in Brugada Syndrome. J Am Heart Assoc 2023; 12:e028706. [PMID: 37158059 DOI: 10.1161/jaha.122.028706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Background The appearance of complete right bundle-branch block (CRBBB) in Brugada syndrome (BrS) is associated with an increased risk of ventricular fibrillation. The pathophysiological mechanism of CRBBB in patients with BrS has not been well established. We aimed to clarify the significance of a conduction delay zone associated with arrhythmias on CRBBB using body surface mapping in patients with BrS. Methods and Results Body surface mapping was recorded in 11 patients with BrS and 8 control patients both with CRBBB. CRBBB in control patients was transiently exhibited by unintentional catheter manipulation (proximal RBBB). Ventricular activation time maps were constructed for both of the groups. We divided the anterior chest into 4 areas (inferolateral right ventricle [RV], RV outflow tract [RVOT], intraventricular septum, and left ventricle) and compared activation patterns between the 2 groups. Excitation propagated to the RV from the left ventricle through the intraventricular septum with activation delay in the entire RV in the control group (proximal RBBB pattern). In 7 patients with BrS, excitation propagated from the inferolateral RV to the RVOT with significant regional activation delay. The remaining 4 patients with BrS showed a proximal RBBB pattern with the RVOT activation delay. The ventricular activation time in the inferolateral RV was significantly shorter in patients with BrS without a proximal RBBB pattern than in control patients. Conclusions The CRBBB morphology in patients with BrS consisted of 2 mechanisms: (1) significantly delayed conduction in the RVOT and (2) proximal RBBB with RVOT conduction delay. Significant RVOT conduction delay without proximal RBBB resulted in CRBBB morphology in patients with BrS.
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Affiliation(s)
- Yoshimasa Morimoto
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
- Department of Cardiovascular Medicine Fukuyama City Hospital Hiroshima Japan
| | - Hiroshi Morita
- Department of Cardiovascular Therapeutics Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Kentaro Ejiri
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
- Department of Epidemiology Johns Hopkins Bloomberg School of Public Health Baltimore MD USA
| | - Tomofumi Mizuno
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Takuro Masuda
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Akira Ueoka
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Saori Asada
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Masakazu Miyamoto
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Satoshi Kawada
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Koji Nakagawa
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Nobuhiro Nishii
- Department of Cardiovascular Therapeutics Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Kazufumi Nakamura
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
| | - Hiroshi Ito
- Department of Cardiovascular Medicine Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama Japan
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8
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Popa IP, Șerban DN, Mărănducă MA, Șerban IL, Tamba BI, Tudorancea I. Brugada Syndrome: From Molecular Mechanisms and Genetics to Risk Stratification. Int J Mol Sci 2023; 24:ijms24043328. [PMID: 36834739 PMCID: PMC9967917 DOI: 10.3390/ijms24043328] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/13/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Brugada syndrome (BrS) is a rare hereditary arrhythmia disorder, with a distinctive ECG pattern, correlated with an increased risk of ventricular arrhythmias and sudden cardiac death (SCD) in young adults. BrS is a complex entity in terms of mechanisms, genetics, diagnosis, arrhythmia risk stratification, and management. The main electrophysiological mechanism of BrS requires further research, with prevailing theories centered on aberrant repolarization, depolarization, and current-load match. Computational modelling, pre-clinical, and clinical research show that BrS molecular anomalies result in excitation wavelength (k) modifications, which eventually increase the risk of arrhythmia. Although a mutation in the SCN5A (Sodium Voltage-Gated Channel Alpha Subunit 5) gene was first reported almost two decades ago, BrS is still currently regarded as a Mendelian condition inherited in an autosomal dominant manner with incomplete penetrance, despite the recent developments in the field of genetics and the latest hypothesis of additional inheritance pathways proposing a more complex mode of inheritance. In spite of the extensive use of the next-generation sequencing (NGS) technique with high coverage, genetics remains unexplained in a number of clinically confirmed cases. Except for the SCN5A which encodes the cardiac sodium channel NaV1.5, susceptibility genes remain mostly unidentified. The predominance of cardiac transcription factor loci suggests that transcriptional regulation is essential to the Brugada syndrome's pathogenesis. It appears that BrS is a multifactorial disease, which is influenced by several loci, each of which is affected by the environment. The primary challenge in individuals with a BrS type 1 ECG is to identify those who are at risk for sudden death, researchers propose the use of a multiparametric clinical and instrumental strategy for risk stratification. The aim of this review is to summarize the latest findings addressing the genetic architecture of BrS and to provide novel perspectives into its molecular underpinnings and novel models of risk stratification.
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Affiliation(s)
- Irene Paula Popa
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
| | - Dragomir N. Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Minela Aida Mărănducă
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Ionela Lăcrămioara Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Bogdan Ionel Tamba
- Department of Pharmacology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
- Correspondence:
| | - Ionuț Tudorancea
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
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9
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Martini B, Martini N, De Mattia L, Buja G. Delayed depolarization and histologic abnormalities underlie the Brugada syndrome. Pacing Clin Electrophysiol 2023; 46:172-181. [PMID: 36542434 DOI: 10.1111/pace.14650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/01/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022]
Abstract
Brugada syndrome (BrS) is a controversial disease whose pathophysiology is still far from being fully understood. Unlike other cardiological disorders, a definite etiology has not yet been established so that it could be summarized under two main chapters: "functional" or "organic", "repolarization" or "depolarization" disorder. Despite initial descriptions leaned towards the organic substrate and delayed depolarization features, functional and repolarization theories have attracted most of the Cardiological attention for many years. Data from electrocardiography, endocavitary tracings, electroanatomic mapping and histopathology, however, demonstrated that BrS is mainly characterized by structural myocardial changes mostly at the right ventricular outflow tract (RVOT), but also at the right ventricle (RV) and by delayed conduction at the same sites. Conduction disorders at different levels may also be present and identify patients at high risk for major arrhythmic events. The aim of the present review is to provide the current state of art of the pathophysiology of BrS, focusing on electro-vectorcardiography and electrophysiological features, histopathology, echocardiography, and cardiac magnetic resonance imaging (CMRI).
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Affiliation(s)
| | - Nicolò Martini
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, Padua, Italy
| | | | - Gianfranco Buja
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, Padua, Italy
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10
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Biasi N, Seghetti P, Tognetti A. Diffuse fibrosis and repolarization disorders explain ventricular arrhythmias in Brugada syndrome: a computational study. Sci Rep 2022; 12:8530. [PMID: 35595775 PMCID: PMC9123016 DOI: 10.1038/s41598-022-12239-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 05/06/2022] [Indexed: 11/20/2022] Open
Abstract
In this work, we reported a computational study to quantitatively determine the individual contributions of three candidate arrhythmic factors associated with Brugada Syndrome. In particular, we focused our analysis on the role of structural abnormalities, dispersion of repolarization, and size of the diseased region. We developed a human phenomenological model capable of replicating the action potential characteristics both in Brugada Syndrome and in healthy conditions. Inspired by physiological observations, we employed the phenomenological model in a 2D geometry resembling the pathological RVOT coupled with healthy epicardial tissue. We assessed the insurgence of sustained reentry as a function of electrophysiological and structural abnormalities. Our computational study indicates that both structural and repolarization abnormalities are essential to induce sustained reentry. Furthermore, our results suggest that neither dispersion of repolarization nor structural abnormalities are sufficient on their own to induce sustained reentry. It should be noted how our study seems to explain an arrhythmic mechanism that unifies the classic repolarization and depolarization hypotheses of the pathophysiology of the Brugada Syndrome. Finally, we believe that this work may offer a new perspective on the computational and clinical investigation of Brugada Syndrome and its arrhythmic behaviour.
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Affiliation(s)
- Niccoló Biasi
- Department of Information Engineering, University of Pisa, Pisa, Italy.
| | - Paolo Seghetti
- Institute of Life Sciences, Scuola Superiore Sant'Anna, Pisa, Italy.,National Research Council, Institute of Clinical Physiology, Pisa, Italy
| | - Alessandro Tognetti
- Department of Information Engineering, University of Pisa, Pisa, Italy.,Research Centre "E. Piaggio", University of Pisa, Pisa, Italy
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11
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Mechanism of the Effects of Sodium Channel Blockade on the Arrhythmogenic Substrate of Brugada Syndrome. Heart Rhythm 2021; 19:407-416. [PMID: 34742919 DOI: 10.1016/j.hrthm.2021.10.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND The mechanisms by which sodium channel blockade and high-rate pacing modify electrogram substrates of Brugada syndrome (BrS) have not been elucidated. OBJECTIVES To determine the effect of ajmaline and high pacing rate on the BrS substrates. METHODS Thirty-two BrS patients (age 40 ± 12 years) with frequent ventricular fibrillation (VF) episodes underwent right ventricular outflow tract (RVOT) substrate electroanatomical and electrocardiogram imaging (ECGI) mapping before and after ajmaline administration and during high-rate atrial pacing. In 4 patients, epicardial mapping was performed using open thoracotomy with targeted biopsies. RESULTS Ajmaline increased the activation time delay in the substrate (33%; p = 0.002), ST elevation in the right precordial leads (74%; p < 0.0001), and the area of delayed activation (170%; p < 0.0001), coinciding with increased substrate size (75%; p < 0.0001). High atrial pacing rate increased the abnormal electrogram (EGM) duration at the RVOT areas from 112 ± 48 to 143 ± 66 ms (p = 0.003) and produced intermittent conduction block and/or excitation failure at the substrate sites, especially after ajmaline. Biopsies from the 4 patients with thoracotomy showed epicardial fibrosis where EGMs were normal at baseline but became fractionated after ajmaline. In some areas, local activation was absent and unipolar EGMs had a monophasic morphology resembling the shape of the action potential. CONCLUSIONS INa reduction with ajmaline severely compromises impulse conduction at the BrS fibrotic substrates by producing fractionated EGMs, conduction block, or excitation failure, leading to the Brugada ECG pattern and favoring VF genesis.
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12
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Multisite conduction block in the epicardial substrate of Brugada syndrome. Heart Rhythm 2021; 19:417-426. [PMID: 34737095 DOI: 10.1016/j.hrthm.2021.10.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/21/2021] [Accepted: 10/26/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND The Brugada pattern manifests as a spontaneous variability of the electrocardiographic marker, suggesting a variability of the underlying electrical substrate. OBJECTIVE The purpose of this study was to investigate the response of the epicardial substrate of Brugada syndrome (BrS) to programmed ventricular stimulation and to Na blocker infusion. METHODS We investigated 6 patients (all male; mean age 54 ± 14 years) with BrS and recurrent ventricular fibrillation. Five had no type 1 BrS electrocardiogram pattern at admission. They underwent combined epicardial-endocardial mapping using multielectrode catheters. Changes in epicardial electrograms were evaluated during single endocardial extrastimulation and after low-dose ajmaline infusion (0.5 mg/kg in 5 minutes). RESULTS All patients had a region in the anterior epicardial right ventricle with prolonged multicomponent electrograms. Single extrastimulation prolonged late epicardial components by 59 ± 31 ms and in 4 patients abolished epicardial components at some sites, without reactivation by surrounding activated sites. These localized blocks occurred at an initial coupling interval of 335 ± 58 ms and then expanded to other sites, being observed in up to 40% of epicardial sites. Ajmaline infusion prolonged electrogram duration in all and produced localized blocks in 62% of sites in the same patients as during extrastimulation. Epicardial conduction recovery after ajmaline occurred intermittently and at discontinuous sites and produced beat-to-beat changes in local repolarization, resulting in an area of marked electrical disparity. These changes were consistent with models based on microstructural alterations under critical propagation conditions. CONCLUSION In BrS, localized functional conduction blocks occur at multiple epicardial sites and with variable patterns, without being reactivated from the surrounding sites.
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13
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Biventricular Myocardial Fibrosis and Sudden Death in Patients With Brugada Syndrome. J Am Coll Cardiol 2021; 78:1511-1521. [PMID: 34620408 PMCID: PMC8504200 DOI: 10.1016/j.jacc.2021.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 01/24/2023]
Abstract
BACKGROUND Electrophysiological, imaging, and pathological studies have reported the presence of subtle structural abnormalities in hearts from patients with Brugada syndrome (BrS). However, data concerning disease involvement outside of the right ventricular outflow tract are limited. OBJECTIVES This study sought to characterize the presence and distribution of ventricular myocardial fibrosis in a cohort of decedents experiencing sudden cardiac death caused by BrS. METHODS The authors evaluated 28 whole hearts from consecutive sudden cardiac death cases attributed to BrS and 29 hearts from a comparator group comprised of noncardiac deaths (control subjects). Cardiac tissue from 6 regions across the right and left ventricle were stained with Picrosirius red for collagen and tissue composition was determined using image analysis software. Postmortem genetic testing was performed in cases with DNA retained for analysis. RESULTS Of 28 BrS decedents (75% men; median age of death 25 years), death occurred in sleep or at rest in 24 of 28 (86%). The highest proportion of collagen was observed in the epicardial right ventricular outflow tract of the BrS group (23.7%; 95% CI: 20.8%-26.9%). Ventricular myocardium from BrS decedents demonstrated a higher proportion of collagen compared with control subjects (ratio 1.45; 95% CI: 1.22-1.71; P < 0.001), with no significant interactions with respect to sampling location or tissue layer. There was insufficient evidence to support differences in collagen proportion in SCN5A-positive cases (n = 5) when compared with control subjects (ratio 1.23; 95% CI: 0.75-1.43; P = 0.27). CONCLUSIONS Brugada syndrome is associated with increased collagen content throughout right and left ventricular myocardium, irrespective of sampling location or myocardial layer.
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14
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Zoppo F, Gagno G, Perazza L, Cocciolo A, Mugnai G, Vaccari D, Calzolari V. Electroanatomic voltage mapping for tissue characterization beyond arrhythmia definition: A systematic review. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2021; 44:1432-1448. [PMID: 34096635 DOI: 10.1111/pace.14288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/17/2021] [Accepted: 05/30/2021] [Indexed: 11/28/2022]
Abstract
Three-dimensional (3D) reconstruction by means of electroanatomic mapping (EAM) systems, allows for the understanding of the mechanism of focal or re-entrant arrhythmic circuits, which can be identified by means of dynamic (activation and propagation) and static (voltage) color-coded maps. However, besides this conventional use, EAM may offer helpful anatomical and functional information for tissue characterisation in several clinical settings. Today, data regarding electromechanical myocardial viability, scar detection in ischaemic and nonischaemic cardiomyopathy and arrhythmogenic right ventricle dysplasia (ARVC/D) definition are mostly consolidated, while emerging results are becoming available in contexts such as Brugada syndrome and cardiac resynchronisation therapy (CRT) implant procedures. As part of an invasive procedure, EAM has not yet been widely adopted as a stand-alone tool in the diagnostic path. We aim to review the data in the current literature regarding the use of 3D EAM systems beyond the definition of arrhythmia.
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Affiliation(s)
- Franco Zoppo
- Elettrofisiologia, U.O.C. di Cardiologia, Ospedale Civile Gorizia, Gorizia, Italy
| | - Giulia Gagno
- Dipartimento di Cardiologia, Azienda Sanitaria Universitaria Giuliano Isontina, ed Università degli Studi di Trieste, Trieste, Italy
| | - Luca Perazza
- Elettrofisiologia, U.O.C. di Cardiologia, Ospedale Civile Gorizia, Gorizia, Italy
| | - Andrea Cocciolo
- Elettrofisiologia, U.O.C. di Cardiologia, Ospedale Civile Gorizia, Gorizia, Italy
| | - Giacomo Mugnai
- Elettrofisiologia, U.O.C di Cardiologia, Ospedale Civile Arzignano, Vicenza, Italy
| | - Diego Vaccari
- Elettrofisiologia, U.O.C di Cardiologia, Ospedale Civile Feltre, Belluno, Italy
| | - Vittorio Calzolari
- Elettrofisiologia, U.O.C di Cardiologia, Ospedale Civile Treviso, Treviso, Italy
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15
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Rivaud MR, Blok M, Jongbloed MRM, Boukens BJ. How Cardiac Embryology Translates into Clinical Arrhythmias. J Cardiovasc Dev Dis 2021; 8:jcdd8060070. [PMID: 34199178 PMCID: PMC8231901 DOI: 10.3390/jcdd8060070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/31/2021] [Accepted: 06/01/2021] [Indexed: 12/23/2022] Open
Abstract
The electrophysiological signatures of the myocardium in cardiac structures, such as the atrioventricular node, pulmonary veins or the right ventricular outflow tract, are established during development by the spatial and temporal expression of transcription factors that guide expression of specific ion channels. Genome-wide association studies have shown that small variations in genetic regions are key to the expression of these transcription factors and thereby modulate the electrical function of the heart. Moreover, mutations in these factors are found in arrhythmogenic pathologies such as congenital atrioventricular block, as well as in specific forms of atrial fibrillation and ventricular tachycardia. In this review, we discuss the developmental origin of distinct electrophysiological structures in the heart and their involvement in cardiac arrhythmias.
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Affiliation(s)
- Mathilde R. Rivaud
- Department of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam Cardiovascular Sciences, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands;
| | - Michiel Blok
- Department of Anatomy & Embryology, Leiden University Medical Center, Einthovenweg 20, 2300 RC Leiden, The Netherlands; (M.B.); (M.R.M.J.)
| | - Monique R. M. Jongbloed
- Department of Anatomy & Embryology, Leiden University Medical Center, Einthovenweg 20, 2300 RC Leiden, The Netherlands; (M.B.); (M.R.M.J.)
- Department of Cardiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Bastiaan J. Boukens
- Department of Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Amsterdam Cardiovascular Sciences, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands;
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam Cardiovascular Sciences, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
- Correspondence: ; Tel.: +31-(0)20-566-4659
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16
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Zoppo F, Gagno G, Perazza L, Cocciolo A, Mugnai G, Vaccari D, Calzolari V. Electroanatomic voltage mapping and characterisation imaging for "right ventricle arrhythmic syndromes" beyond the arrhythmia definition: a comprehensive review. Int J Cardiovasc Imaging 2021; 37:2347-2357. [PMID: 33761057 DOI: 10.1007/s10554-021-02221-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 03/08/2021] [Indexed: 11/30/2022]
Abstract
Three-dimensional (3D) reconstruction by means of electroanatomic mapping (EAM) systems, allows for the understanding of the mechanism of focal or re-entrant arrhythmic circuits along with pacing techniques. However, besides this conventional use, EAM may offer helpful anatomical and functional information. Data regarding electromechanical scar detection in ischaemic (and nonischaemic) cardiomyopathy are mostly consolidated, while emerging results are becoming available in contexts such as arrhythmogenic right ventricular dysplasia (ARVC/D) definition and Brugada syndrome. As part of an invasive procedure, EAM has not yet been widely adopted as a stand-alone tool in the diagnostic path. We aim to review the current literature regarding the use of 3D EAM systems for right ventricle (RV) functional characterisation beyond the definition of arrhythmia.
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Affiliation(s)
- Franco Zoppo
- Elettrofisiologia, U.O.C. Di Cardiologia, Ospedale Civile Gorizia, Gorizia, Italy.
| | - Giulia Gagno
- Azienda Sanitaria Universitaria Giuliano Isontina - Dipartimento di Cardiologia Trieste, Trieste, Italy
| | - Luca Perazza
- Elettrofisiologia, U.O.C. Di Cardiologia, Ospedale Civile Gorizia, Gorizia, Italy
| | - Andrea Cocciolo
- Elettrofisiologia, U.O.C. Di Cardiologia, Ospedale Civile Gorizia, Gorizia, Italy
| | - Giacomo Mugnai
- Elettrofisiologia, U.O.C Di Cardiologia, Ospedale Civile Arzignano, Vicenza, Italy
| | - Diego Vaccari
- Elettrofisiologia, U.O.C Di Cardiologia, Ospedale Civile Feltre, Belluno, Italy
| | - Vittorio Calzolari
- Elettrofisiologia, U.O.C Di Cardiologia, Ospedale Civile Treviso, Treviso, Italy
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17
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Boukens BJ, Potse M, Coronel R. Fibrosis and Conduction Abnormalities as Basis for Overlap of Brugada Syndrome and Early Repolarization Syndrome. Int J Mol Sci 2021; 22:1570. [PMID: 33557237 PMCID: PMC7913989 DOI: 10.3390/ijms22041570] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 12/16/2022] Open
Abstract
Brugada syndrome and early repolarization syndrome are both classified as J-wave syndromes, with a similar mechanism of arrhythmogenesis and with the same basis for genesis of the characteristic electrocardiographic features. The Brugada syndrome is now considered a conduction disorder based on subtle structural abnormalities in the right ventricular outflow tract. Recent evidence suggests structural substrate in patients with the early repolarization syndrome as well. We propose a unifying mechanism based on these structural abnormalities explaining both arrhythmogenesis and the electrocardiographic changes. In addition, we speculate that, with increasing technical advances in imaging techniques and their spatial resolution, these syndromes will be reclassified as structural heart diseases or cardiomyopathies.
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Affiliation(s)
- Bastiaan J. Boukens
- Department of Experimental Cardiology, Amsterdam University Medical Center, Amsterdam Cardiovascular Sciences, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands;
- Department of Medical Biology, Amsterdam University Medical Center, Amsterdam Cardiovascular Sciences, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Mark Potse
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, 33600 Bordeaux, France;
- UMR5251, Institut de Mathématiques de Bordeaux, Université de Bordeaux, 33400 Talence, France
- Carmen Team, INRIA Bordeaux—Sud-Ouest, 33400 Talence, France
| | - Ruben Coronel
- Department of Experimental Cardiology, Amsterdam University Medical Center, Amsterdam Cardiovascular Sciences, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands;
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Blok M, Boukens BJ. Mechanisms of Arrhythmias in the Brugada Syndrome. Int J Mol Sci 2020; 21:ijms21197051. [PMID: 32992720 PMCID: PMC7582368 DOI: 10.3390/ijms21197051] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 12/13/2022] Open
Abstract
Arrhythmias in Brugada syndrome patients originate in the right ventricular outflow tract (RVOT). Over the past few decades, the characterization of the unique anatomy and electrophysiology of the RVOT has revealed the arrhythmogenic nature of this region. However, the mechanisms that drive arrhythmias in Brugada syndrome patients remain debated as well as the exact site of their occurrence in the RVOT. Identifying the site of origin and mechanism of Brugada syndrome would greatly benefit the development of mechanism-driven treatment strategies.
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Affiliation(s)
- Michiel Blok
- Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Bastiaan J. Boukens
- Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Correspondence: ; Tel.: +31-(0)20-566-4659
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19
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Li KHC, Lee S, Yin C, Liu T, Ngarmukos T, Conte G, Yan GX, Sy RW, Letsas KP, Tse G. Brugada syndrome: A comprehensive review of pathophysiological mechanisms and risk stratification strategies. IJC HEART & VASCULATURE 2020; 26:100468. [PMID: 31993492 PMCID: PMC6974766 DOI: 10.1016/j.ijcha.2020.100468] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 01/01/2020] [Accepted: 01/02/2020] [Indexed: 12/17/2022]
Abstract
Brugada syndrome (BrS) is an inherited ion channel channelopathy predisposing to ventricular arrhythmias and sudden cardiac death. Originally believed to be predominantly associated with mutations in SCN5A encoding for the cardiac sodium channel, mutations of 18 genes other than SCN5A have been implicated in the pathogenesis of BrS to date. Diagnosis is based on the presence of a spontaneous or drug-induced coved-type ST segment elevation. The predominant electrophysiological mechanism underlying BrS remains disputed, commonly revolving around the three main hypotheses based on abnormal repolarization, depolarization or current-load match. Evidence from computational modelling, pre-clinical and clinical studies illustrates that molecular abnormalities found in BrS lead to alterations in excitation wavelength (λ), which ultimately elevates arrhythmic risk. A major challenge for clinicians in managing this condition is the difficulty in predicting the subset of patients who will suffer from life-threatening ventricular arrhythmic events. Several repolarization risk markers have been used thus far, but these neglect the contributions of conduction abnormalities in the form of slowing and dispersion. Indices incorporating both repolarization and conduction based on the concept of λ have recently been proposed. These may have better predictive values than the existing markers. Current treatment options include pharmacological therapy to reduce the occurrence of arrhythmic events or to abort these episodes, and interventions such as implantable cardioverter-defibrillator insertion or radiofrequency ablation of abnormal arrhythmic substrate.
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Affiliation(s)
- Ka Hou Christien Li
- Faculty of Medicine, Newcastle University, Newcastle, United Kingdom.,Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, SAR, PR China
| | - Sharen Lee
- Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, SAR, PR China
| | - Chengye Yin
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China
| | - Tachapong Ngarmukos
- Department of Medicine Faculty of Medicine Ramathibodi Hospital Mahidol University, Bangkok, Thailand
| | - Giulio Conte
- Division of Cardiology, Cardiocentro Ticino, Lugano, Switzerland
| | - Gan-Xin Yan
- Lankenau Institute for Medical Research and Lankenau Medical Center, Wynnewood, PA, USA
| | - Raymond W Sy
- Department of Cardiology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.,Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
| | - Konstantinos P Letsas
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Gary Tse
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China.,Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
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20
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Nagase S, Kamakura T, Kataoka N, Wada M, Yamagata K, Ishibashi K, Inoue YY, Miyamoto K, Noda T, Aiba T, Izumi C, Noguchi T, Yasuda S, Shimizu W, Kamakura S, Kusano K. Low-Voltage Type 1 ECG Is Associated With Fatal Ventricular Tachyarrhythmia in Brugada Syndrome. J Am Heart Assoc 2019; 7:e009713. [PMID: 30571377 PMCID: PMC6404198 DOI: 10.1161/jaha.118.009713] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Background Epicardial mapping can reveal low‐voltage areas on the right ventricular outflow tract in patients with Brugada syndrome with several ventricular fibrillation (VF) episodes. A type 1 ECG is associated with an abnormal electrogram on right ventricular outflow tract epicardium. This study investigated the clinical significance of the amplitude of type 1 ECGs in patients with Brugada syndrome. Methods and Results In 209 patients with Brugada syndrome with a spontaneous type 1 ECG (26 resuscitated from VF, 54 with syncope, and 129 asymptomatic), the amplitude of the ECG in leads exhibiting type 1 was measured among V1 to V3 leads positioned in the standard and upper 1 and 2 intercostal spaces. The number of ECG leads exhibiting type 1 did not differ among groups. The averaged amplitude of type 1 ECG was, however, significantly smaller in the group resuscitated from VF than in the asymptomatic group (P<0.05). Moreover, the minimum amplitude of type 1 ECG was significantly smaller in the group resuscitated from VF than in the group with syncope and the asymptomatic group (P<0.05 and P<0.01, respectively). During follow‐up (56±48 months), VF occurred in 29 patients. Kaplan‐Meier analysis revealed that patients with the minimum amplitude of type 1 ECG lower than or at the median value had a higher incidence of VF (log‐rank test, P<0.01). In multivariate analysis, syncope, past VF episode, and minimum amplitude of type 1 ECG ≤0.8 mV were independent predictors of VF events during follow‐up. Conclusions Low‐voltage type 1 ECG is highly and independently related to fatal ventricular tachyarrhythmia in patients with Brugada syndrome.
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Affiliation(s)
- Satoshi Nagase
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Tsukasa Kamakura
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Naoya Kataoka
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Mitsuru Wada
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Kenichiro Yamagata
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Kohei Ishibashi
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Yuko Y Inoue
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Koji Miyamoto
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Takashi Noda
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Takeshi Aiba
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Chisato Izumi
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Teruo Noguchi
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Satoshi Yasuda
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Wataru Shimizu
- 2 Department of Cardiovascular Medicine Nippon Medical School Tokyo Japan
| | - Shiro Kamakura
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
| | - Kengo Kusano
- 1 Division of Arrhythmia and Electrophysiology Department of Cardiovascular Medicine National Cerebral and Cardiovascular Center Suita Japan
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21
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Watanabe A, Morita H, Kawada S, Tachibana M, Morimoto Y, Ito H. Open chest epicardial mapping in an asymptomatic patient with Brugada syndrome. HeartRhythm Case Rep 2019; 5:501-504. [PMID: 31700794 PMCID: PMC6831756 DOI: 10.1016/j.hrcr.2019.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Atsuyuki Watanabe
- Department of Cardiovascular Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama City, Japan
| | - Hiroshi Morita
- Department of Cardiovascular Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama City, Japan
| | - Satoshi Kawada
- Department of Cardiovascular Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama City, Japan
| | - Motomi Tachibana
- Department of Cardiovascular Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama City, Japan
| | - Yoshimasa Morimoto
- Department of Cardiovascular Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama City, Japan
| | - Hiroshi Ito
- Department of Cardiovascular Medicine, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama City, Japan
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22
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Bhar-Amato J, Finlay M, Santos D, Orini M, Chaubey S, Vyas V, Taggart P, Grace AA, Huang CLH, Ben Simon R, Tinker A, Lambiase PD. Pharmacological Modulation of Right Ventricular Endocardial-Epicardial Gradients in Brugada Syndrome. Circ Arrhythm Electrophysiol 2019; 11:e006330. [PMID: 30354290 DOI: 10.1161/circep.118.006330] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background We explored the hypothesis that increased cholinergic tone exerts its proarrhythmic effects in Brugada syndrome (BrS) through increasing dispersion of transmural repolarization in patients with spontaneous and drug-induced BrS. Methods BrS and supraventricular tachycardia patients were studied after deploying an Ensite Array in the right ventricular outflow tract and a Cardima catheter in the great cardiac vein to record endo and epicardial signals, respectively. S1-S2 restitution curves from the right ventricular apex were conducted at baseline and after edrophonium challenge to promote increased cholinergic tone. The local unipolar electrograms were then analyzed to study transmural conduction and repolarization dynamics. Results The study included 8 BrS patients (5 men:3 women; mean age, 56 years) and 8 controls patients with supraventricular tachycardia (5 men:3 women; mean age, 48 years). Electrophysiological studies in controls demonstrated shorter endocardial than epicardial right ventricular activation times (mean difference: 26 ms; P<0.001). In contrast, patients with BrS showed longer endocardial than epicardial activation time (mean difference: -15 ms; P=0.001). BrS hearts, compared with controls, showed significantly larger transmural gradients in their activation recovery intervals (mean intervals, 20.5 versus 3.5 ms; P<0.01), with longer endocardial than epicardial activation recovery intervals. Edrophonium challenge increased such gradients in both controls (to a mean of 16 ms [ P<0.001]) and BrS (to 29.7 ms; P<0.001). However, these were attributable to epicardial and endocardial activation recovery interval prolongations in control and BrS hearts, respectively. Dynamic changes in repolarization gradients were also observed across the BrS right ventricular wall in BrS. Conclusions Differential contributions of conduction and repolarization were identified in BrS which critically modulated transmural dispersion of repolarization with significant cholinergic effects only identified in the patients with BrS. This has important implications for explaining the proarrhythmic effects of increased vagal tone in BrS, as well as evaluating autonomic modulation and epicardial ablation as therapeutic strategies.
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Affiliation(s)
- Justine Bhar-Amato
- University College London, United Kingdom (J.B.-A., D.S., M.O., P.T., P.D.L.)
| | - Malcolm Finlay
- Barts Heart Centre, London, United Kingdom (M.F., V.V., R.B.S., P.D.L.).,Queen Mary's College London, United Kingdom (M.F., A.T.)
| | - Diogo Santos
- University College London, United Kingdom (J.B.-A., D.S., M.O., P.T., P.D.L.)
| | - Michele Orini
- University College London, United Kingdom (J.B.-A., D.S., M.O., P.T., P.D.L.)
| | | | - Vishal Vyas
- Barts Heart Centre, London, United Kingdom (M.F., V.V., R.B.S., P.D.L.)
| | - Peter Taggart
- University College London, United Kingdom (J.B.-A., D.S., M.O., P.T., P.D.L.)
| | - Andrew A Grace
- Cambridge University, United Kingdom (A.A.G., C.L.-H.H.)
| | | | - Ron Ben Simon
- University College London, United Kingdom (J.B.-A., D.S., M.O., P.T., P.D.L.).,Barts Heart Centre, London, United Kingdom (M.F., V.V., R.B.S., P.D.L.)
| | - Andrew Tinker
- Queen Mary's College London, United Kingdom (M.F., A.T.)
| | - Pier D Lambiase
- University College London, United Kingdom (J.B.-A., D.S., M.O., P.T., P.D.L.).,Barts Heart Centre, London, United Kingdom (M.F., V.V., R.B.S., P.D.L.)
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23
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Riede FN, Gutmann M, Meier Y, Leibundgut G. Electrical storm after conus branch occlusion. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.ihjccr.2018.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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24
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Aleong RG, Chandara M. Management of Brugada Syndrome in the Developing Countries. CURRENT CARDIOVASCULAR RISK REPORTS 2018. [DOI: 10.1007/s12170-018-0595-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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25
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Abstract
Early repolarization, Brugada syndrome, and pathologic J waves have been described for decades, but only recently experimental and clinical data have allowed reconciliation of Brugada and Early Repolarization under the common definition of J-wave syndromes. The concept was derived from studies showing, in both conditions, the presence of transmural dispersion of repolarization, localized conduction abnormalities, and abnormal transition between QRS and ST segment on electrocardiogram. Although several clinical studies have addressed the clinical presentation and epidemiology of J-wave syndromes, relevant knowledge gaps exist. Incomplete pathophysiologic understanding and uncertain electrocardiographic definitions limit effective risk stratification. Here, we review the current knowledge and recommendations for diagnosis and clinical management of these arrhythmogenic disorders.
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Affiliation(s)
- Silvia G Priori
- Molecular Cardiology, ICS Maugeri, IRCCS, Pavia, Italy; Department of Molecular Medicine, University of Pavia, Pavia, Italy.
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26
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Wilde AAM, Amin AS. Clinical Spectrum of SCN5A Mutations: Long QT Syndrome, Brugada Syndrome, and Cardiomyopathy. JACC Clin Electrophysiol 2018; 4:569-579. [PMID: 29798782 DOI: 10.1016/j.jacep.2018.03.006] [Citation(s) in RCA: 190] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 03/02/2018] [Accepted: 03/08/2018] [Indexed: 12/13/2022]
Abstract
SCN5A gene encodes the pore-forming ion-conducting α-subunit of the cardiac sodium channel (Nav1.5), which is responsible for the initiation and propagation of action potentials and thereby determines cardiac excitability and conduction of electrical stimuli through the heart. The importance of Nav1.5 for normal cardiac electricity is reflected by various disease entities that can be caused by mutations in SCN5A. Gain-of-function mutations in SCN5A lead to more sodium influx into cardiomyocytes through aberrant channel gating and cause long QT syndrome, a primary electrical disease of the heart. Loss-of-function mutations in SCN5A lead to lower expression levels of SCN5A or production of defective Nav1.5 proteins and cause Brugada syndrome, an electrical disease with minor structural changes in the heart. In addition, both loss- and gain-of-function mutations may cause dilated cardiomyopathy, which is an arrhythmogenic disease with gross structural defects of the left ventricle (and sometimes both ventricles). Other SCN5A-related diseases are multifocal ectopic premature Purkinje-related complexes (gain-of-function mutations), isolated cardiac conduction defect (loss-of-function mutations), sick sinus syndrome (loss-of-function mutations), atrial fibrillation (loss-of-function or gain-of-function mutations), and overlap syndromes (mutations with both loss-of-function and gain-of-function effects). Growing insights into the role of SCN5A in health and disease has enabled clinicians to lay out gene-specific risk stratification schemes and mutation-specific diagnostic and therapeutic strategies in the management of patients with a SCN5A mutation. This review summarizes currently available knowledge about the pathophysiological mechanisms of SCN5A mutations and describes how this knowledge can be used to manage patients suffering from potentially lethal cardiac diseases.
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Affiliation(s)
- Arthur A M Wilde
- Heart Centre Academic Medical Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands; Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Kingdom of Saudi Arabia; Department of Medicine, Columbia University Irving Medical Centre, New York, New York.
| | - Ahmad S Amin
- Heart Centre Academic Medical Center, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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27
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Cerrone M. Controversies in Brugada syndrome. Trends Cardiovasc Med 2017; 28:284-292. [PMID: 29254832 DOI: 10.1016/j.tcm.2017.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/16/2017] [Accepted: 11/21/2017] [Indexed: 12/19/2022]
Abstract
The Brugada syndrome is an inherited channelopathy associated with increased risk of ventricular arrhythmias and sudden death, often occurring during sleep or resting conditions. Although this entity has been described more than 20 years ago, it remains one of the most debated among channelopathies, with several open questions on its genetic substrate, arrhythmia mechanisms, and clinical management. Studies on the genetics and physiopathology bases of the Brugada syndrome have opened novel investigative pathways and concepts that are now entering the field of cardiovascular genetics and are applied to other inherited arrhythmias. In this perspective, Brugada syndrome can be seen as an example on how basic science discoveries have influenced clinical management and led to novel therapeutic approaches.
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Affiliation(s)
- Marina Cerrone
- Cardiovascular Genetics Program, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, NY.
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28
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Leong KMW, Ng FS, Yao C, Roney C, Taraborrelli P, Linton NWF, Whinnett ZI, Lefroy DC, Davies DW, Boon Lim P, Harding SE, Peters NS, Kanagaratnam P, Varnava AM. ST-Elevation Magnitude Correlates With Right Ventricular Outflow Tract Conduction Delay in Type I Brugada ECG. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.117.005107. [PMID: 29038102 DOI: 10.1161/circep.117.005107] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 08/17/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND The substrate location and underlying electrophysiological mechanisms that contribute to the characteristic ECG pattern of Brugada syndrome (BrS) are still debated. Using noninvasive electrocardiographical imaging, we studied whole heart conduction and repolarization patterns during ajmaline challenge in BrS individuals. METHODS AND RESULTS A total of 13 participants (mean age, 44±12 years; 8 men), 11 concealed patients with type I BrS and 2 healthy controls, underwent an ajmaline infusion with electrocardiographical imaging and ECG recordings. Electrocardiographical imaging activation recovery intervals and activation timings across the right ventricle (RV) body, outflow tract (RVOT), and left ventricle were calculated and analyzed at baseline and when type I BrS pattern manifested after ajmaline infusion. Peak J-ST point elevation was calculated from the surface ECG and compared with the electrocardiographical imaging-derived parameters at the same time point. After ajmaline infusion, the RVOT had the greatest increase in conduction delay (5.4±2.8 versus 2.0±2.8 versus 1.1±1.6 ms; P=0.007) and activation recovery intervals prolongation (69±32 versus 39±29 versus 21±12 ms; P=0.0005) compared with RV or left ventricle. In controls, there was minimal change in J-ST point elevation, conduction delay, or activation recovery intervals at all sites with ajmaline. In patients with BrS, conduction delay in RVOT, but not RV or left ventricle, correlated to the degree of J-ST point elevation (Pearson R, 0.81; P<0.001). No correlation was found between J-ST point elevation and activation recovery intervals prolongation in the RVOT, RV, or left ventricle. CONCLUSIONS Magnitude of ST (J point) elevation in the type I BrS pattern is attributed to degree of conduction delay in the RVOT and not prolongation in repolarization time.
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Affiliation(s)
- Kevin M W Leong
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.).
| | - Fu Siong Ng
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Cheng Yao
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Caroline Roney
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Patricia Taraborrelli
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Nicholas W F Linton
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Zachary I Whinnett
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - David C Lefroy
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - D Wyn Davies
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Phang Boon Lim
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Sian E Harding
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Nicholas S Peters
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Prapa Kanagaratnam
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.)
| | - Amanda M Varnava
- From the National Heart and Lung Institute, Imperial College London, United Kingdom (K.M.W.L., F.S.N., C.R., N.W.F.L., Z.I.W., P.B.L., S.E.H., N.S.P., P.K.); Imperial College Healthcare NHS Trust, London, United Kingdom (K.M.W.L., F.S.N., P.T., N.W.F.L., Z.I.W., D.C.L., D.W.D., P.B.L., N.S.P., P.K., A.M.V.); and Medtronic Ltd, Watford, United Kingdom (C.Y.).
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Morita H, Watanabe A, Kawada S, Miyamoto M, Morimoto Y, Nakagawa K, Nishii N, Nakamura K, Ito H. Identification of electrocardiographic risk markers for the initial and recurrent episodes of ventricular fibrillation in patients with Brugada syndrome. J Cardiovasc Electrophysiol 2017; 29:107-114. [DOI: 10.1111/jce.13349] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/17/2017] [Accepted: 09/19/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Hiroshi Morita
- Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine; Dentistry and Pharmaceutical Sciences; Okayama Japan
| | - Atsuyuki Watanabe
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences; Okayama University Graduate School of Medicine and Dentistry; Okayama Japan
| | - Satoshi Kawada
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences; Okayama University Graduate School of Medicine and Dentistry; Okayama Japan
| | - Masakazu Miyamoto
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences; Okayama University Graduate School of Medicine and Dentistry; Okayama Japan
| | - Yoshimasa Morimoto
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences; Okayama University Graduate School of Medicine and Dentistry; Okayama Japan
| | - Koji Nakagawa
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences; Okayama University Graduate School of Medicine and Dentistry; Okayama Japan
| | - Nobuhiro Nishii
- Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine; Dentistry and Pharmaceutical Sciences; Okayama Japan
| | - Kazufumi Nakamura
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences; Okayama University Graduate School of Medicine and Dentistry; Okayama Japan
| | - Hiroshi Ito
- Department of Cardiovascular Medicine, Dentistry and Pharmaceutical Sciences; Okayama University Graduate School of Medicine and Dentistry; Okayama Japan
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30
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Vigmond EJ, Efimov IR, Rentschler SL, Coronel R, Boukens BJ. Fractionated electrograms with ST-segment elevation recorded from the human right ventricular outflow tract. HeartRhythm Case Rep 2017; 3:546-550. [PMID: 29204352 PMCID: PMC5688235 DOI: 10.1016/j.hrcr.2017.08.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- Edward J Vigmond
- L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Fondation Bordeaux University, Pessac, France.,University of Bordeaux, IMB, UMR 5251, Talence, France
| | - Igor R Efimov
- L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Fondation Bordeaux University, Pessac, France.,Department of Biomedical Engineering, George Washington University, Washington, DC
| | - Stacey L Rentschler
- Department of Medicine and Developmental Biology, Washington University in St Louis, St Louis, Missouri
| | - Ruben Coronel
- L'Institut de RYthmologie et de modélisation Cardiaque (LIRYC), Fondation Bordeaux University, Pessac, France.,Department of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Bastiaan J Boukens
- University of Bordeaux, IMB, UMR 5251, Talence, France.,Department of Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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31
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Nagase S, Tanaka M, Morita H, Nakagawa K, Wada T, Murakami M, Nishii N, Nakamura K, Ito H, Ohe T, Kusano KF. Local Left Ventricular Epicardial J Waves and Late Potentials in Brugada Syndrome Patients with Inferolateral Early Repolarization Pattern. Front Physiol 2017; 8:14. [PMID: 28184198 PMCID: PMC5266732 DOI: 10.3389/fphys.2017.00014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/09/2017] [Indexed: 01/27/2023] Open
Abstract
Background: Brugada syndrome (BrS) is characterized by J-point or ST-segment elevation on electrocardiograms (ECGs) and increased risk of ventricular fibrillation (VF). In BrS, epicardial depolarization abnormality with delayed potential on the right ventricular outflow tract is reportedly the predominant mechanism underlying VF. Yet VF occurrence is also associated with early repolarization (ER) pattern in the inferolateral ECG leads, which may represent the inferior and/or left lateral ventricular myocardium. The aim of this study was to examine epicardial electrograms recorded directly at the left ventricle (LV) in BrS patients after VF episodes. Methods: In 12 BrS patients who had experienced VF episodes and 17 control subjects, a multipolar catheter was introduced into the left lateral coronary vein for unipolar and bipolar electrogram recordings at the LV epicardium. Both inferior and lateral ER patterns on ECG were observed in three BrS patients and six control subjects. Results: In the epicardium, prominent J waves were detected using unipolar recording, and potentials after the QRS complex were detected using bipolar recording in three of the 12 BrS patients. These three patients also showed both inferior and lateral ER patterns on ECG. Neither prominent J waves nor potentials after the QRS complex were recorded at the endocardium of the LV in any of these three patients; nor were they seen at the epicardium in any of the control subjects. These features were accentuated on pilsicainide administration (n = 2) but diminished on constant atrial pacing (n = 3) and isoproterenol administration (n = 1). The J waves observed through unipolar recording coincided with the potentials after QRS complex observed through bipolar recording and with the inferolateral ER patterns on ECG. Conclusions: We recorded prominent J waves in unipolar electrogram and potentials after QRS complex in bipolar electrogram at the LV epicardium in BrS patients with global ER pattern. The prominent J waves coincided with the potentials after QRS complex and the inferolateral ER pattern on ECG. The characteristics of the inferolateral ER pattern on ECG in these patients primarily represent depolarization feature.
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Affiliation(s)
- Satoshi Nagase
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center Osaka, Japan
| | - Masamichi Tanaka
- Departments of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama, Japan
| | - Hiroshi Morita
- Departments of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama, Japan
| | - Koji Nakagawa
- Departments of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama, Japan
| | - Tadashi Wada
- Departments of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama, Japan
| | - Masato Murakami
- Departments of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama, Japan
| | - Nobuhiro Nishii
- Departments of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama, Japan
| | - Kazufumi Nakamura
- Departments of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama, Japan
| | - Hiroshi Ito
- Departments of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences Okayama, Japan
| | - Tohru Ohe
- Department of Cardiovascular Medicine, Sakakibara Heart Institute of Okayama Okayama, Japan
| | - Kengo F Kusano
- Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center Osaka, Japan
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32
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Martini B, Martini N, Dorantes Sánchez M, Márquez MF, Zhang L, Fontaine G, Nava A. [Clues of an underlying organic substrate in the Brugada Syndrome]. ARCHIVOS DE CARDIOLOGIA DE MEXICO 2016; 87:49-60. [PMID: 28038951 DOI: 10.1016/j.acmx.2016.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 10/06/2016] [Accepted: 10/11/2016] [Indexed: 10/20/2022] Open
Affiliation(s)
- Bortolo Martini
- Unidad Cardiovascular, Hospital Alto Vicentino, Santorso, Italia.
| | - Nicolò Martini
- Colegio Médico, Universidad de Medicina de Ferrara, Ferrara, Italia
| | - Margarita Dorantes Sánchez
- Servicio de Arritmias y Estimulación Cardiaca, Instituto de Cardiología y Cirugía Cardiovascular, La Habana, Cuba
| | - Manlio F Márquez
- Servicio de Electrocardiología, Instituto Nacional de Cardiología Ignacio Chávez, Ciudad de México, México
| | - Li Zhang
- Instituto Lankenau de Investigación Médica, Colegio Médico Jefferson, Filadelfia, Estados Unidos
| | - Guy Fontaine
- Unidad de Ritmología, Instituto de Cardiología, Hospital de La Pitié-Salpêtrière, París, Francia
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33
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Transmural electrophysiological heterogeneity, the T-wave and ventricular arrhythmias. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2016; 122:202-214. [DOI: 10.1016/j.pbiomolbio.2016.05.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/21/2016] [Accepted: 05/03/2016] [Indexed: 01/05/2023]
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34
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Characterization of the epicardial substrate for catheter ablation of Brugada syndrome. Heart Rhythm 2016; 13:2151-2158. [DOI: 10.1016/j.hrthm.2016.07.025] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Indexed: 11/23/2022]
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35
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Tse G, Liu T, Li KHC, Laxton V, Chan YWF, Keung W, Li RA, Yan BP. Electrophysiological Mechanisms of Brugada Syndrome: Insights from Pre-clinical and Clinical Studies. Front Physiol 2016; 7:467. [PMID: 27803673 PMCID: PMC5067537 DOI: 10.3389/fphys.2016.00467] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/27/2016] [Indexed: 12/19/2022] Open
Abstract
Brugada syndrome (BrS), is a primary electrical disorder predisposing affected individuals to sudden cardiac death via the development of ventricular tachycardia and fibrillation (VT/VF). Originally, BrS was linked to mutations in the SCN5A, which encodes for the cardiac Na+ channel. To date, variants in 19 genes have been implicated in this condition, with 11, 5, 3, and 1 genes affecting the Na+, K+, Ca2+, and funny currents, respectively. Diagnosis of BrS is based on ECG criteria of coved- or saddle-shaped ST segment elevation and/or T-wave inversion with or without drug challenge. Three hypotheses based on abnormal depolarization, abnormal repolarization, and current-load-mismatch have been put forward to explain the electrophysiological mechanisms responsible for BrS. Evidence from computational modeling, pre-clinical, and clinical studies illustrates that molecular abnormalities found in BrS lead to alterations in excitation wavelength (λ), which ultimately elevates arrhythmic risk. A major challenge for clinicians in managing this condition is the difficulty in predicting the subset of patients who will suffer from life-threatening VT/VF. Several repolarization risk markers have been used thus far, but these neglect the contributions of conduction abnormalities in the form of slowing and dispersion. Indices incorporating both repolarization and conduction and based on the concept of λ have recently been proposed. These may have better predictive values than the existing markers.
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Affiliation(s)
- Gary Tse
- Department of Medicine and Therapeutics, Chinese University of Hong KongHong Kong, Hong Kong
- Li Ka Shing Institute of Health Sciences, Chinese University of Hong KongHong Kong, Hong Kong
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical UniversityTianjin, China
| | - Ka H. C. Li
- Faculty of Medicine, Newcastle UniversityNewcastle, UK
| | - Victoria Laxton
- Intensive Care Department, Royal Brompton and Harefield NHS TrustLondon, UK
| | - Yin W. F. Chan
- School of Biological Sciences, University of CambridgeCambridge, UK
| | - Wendy Keung
- Stem Cell and Regenerative Medicine Consortium, Li Ka Shing Faculty of Medicine, The University of Hong KongPokfulam, Hong Kong
| | - Ronald A. Li
- Ming Wai Lau Centre for Reparative Medicine, Karolinska InstitutetSolna, Sweden
| | - Bryan P. Yan
- Department of Medicine and Therapeutics, Chinese University of Hong KongHong Kong, Hong Kong
- Department of Epidemiology and Preventive Medicine, Monash UniversityMelbourne, VIC, Australia
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36
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Martini B, Zolla C, Guglielmi F, Toffanin GL, Cannas S, Martini N, Arancio R. Who is the guilty among these two silent killers? HeartRhythm Case Rep 2016; 3:33-35. [PMID: 28491763 PMCID: PMC5420017 DOI: 10.1016/j.hrcr.2016.08.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Bortolo Martini
- Cardiac Unit, Santorso Hospital, Santorso, Italy
- Address reprint requests and correspondence: Dr Bortolo Martini, Cardiac Unit, Santorso Hospital, Via Garziere 42, 36014 Santorso (Vicenza), Italy.Cardiac Unit, Santorso Hospital, Via Garziere 42, 36014 Santorso (Vicenza)Italy
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37
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Kataoka N, Mizumaki K, Nakatani Y, Sakamoto T, Yamaguchi Y, Tsujino Y, Nishida K, Inoue H. Paced QRS fragmentation is associated with spontaneous ventricular fibrillation in patients with Brugada syndrome. Heart Rhythm 2016; 13:1497-503. [DOI: 10.1016/j.hrthm.2016.03.050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Indexed: 12/28/2022]
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38
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Kumar S, Kalman JM. Brugada Syndrome Diagnosed from the ECG Leads in the High Intercostal Spaces: Searching for Answers from a Higher Source? J Cardiovasc Electrophysiol 2016; 27:944-6. [PMID: 27221147 DOI: 10.1111/jce.13016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Saurabh Kumar
- Arrythmia Service, Cardiovascular Division, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jonathan M Kalman
- Department of Cardiology, Division of Medicine, The Royal Melbourne Hospital and University of Melbourne, Melbourne, Australia
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39
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Low amplitude ECG and QRS fragmentation in provocable coved-type ST-segment elevation on surface ECG are strong predictors of a continuum between arrhythmogenic cardiomypathy and Brugada syndrome. Int J Cardiol 2016; 214:148-50. [PMID: 27061648 DOI: 10.1016/j.ijcard.2016.03.113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 03/19/2016] [Indexed: 11/22/2022]
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40
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The history of Brugada syndrome -- Continuum with arrhythmogenic cardiomyopathy or lone disease? Int J Cardiol 2016; 211:84-5. [PMID: 26982088 DOI: 10.1016/j.ijcard.2016.02.132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 02/10/2016] [Accepted: 02/28/2016] [Indexed: 11/23/2022]
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41
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Peters S. Ion channel diseases as a part in the definition and classification of cardiomyopathies recently confirmed in Brugada syndrome. Int J Cardiol 2016; 207:103. [PMID: 26797342 DOI: 10.1016/j.ijcard.2016.01.136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 01/05/2016] [Indexed: 12/27/2022]
Affiliation(s)
- Stefan Peters
- St.Elisabeth Hospital gGmbH Salzgitter, Liebenhaller Str. 20, 38259 Salzgitter, Germany.
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42
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Eckhardt LL. Monomorphic ventricular tachycardia in Brugada syndrome: True-true but related? Heart Rhythm 2015; 13:683-5. [PMID: 26632641 DOI: 10.1016/j.hrthm.2015.11.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Indexed: 01/09/2023]
Affiliation(s)
- Lee L Eckhardt
- Cardiac Electrophysiology, Cellular and Molecular Arrhythmia Research Program, Division of Cardiovascular Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
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