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Occhetta E, De Vecchi F, Barbonaglia L, Devecchi C, Matta M, Malacrida M, Patti G, Rametta F. Can specific ECG markers identify a pharmacologically induced type 1 Brugada pattern? Insights from a large, single-center cohort. J Electrocardiol 2023; 81:123-131. [PMID: 37688842 DOI: 10.1016/j.jelectrocard.2023.08.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/16/2023] [Accepted: 08/28/2023] [Indexed: 09/11/2023]
Abstract
BACKGROUND In patients with a type 2 or 3 Brugada pattern, the pharmacological (IC drugs) induction of a type 1 pattern confirms the diagnosis of Brugada syndrome. OBJECTIVE To evaluate the value of various ECG markers in predicting IC drug test results. METHODS We retrospectively analysed 443 consecutive patients referred to our Center (from January 2010 to December 2019) to undergo Ajmaline/Flecainide testing; all had a type 2 or 3 Brugada pattern or were relatives with Brugada syndrome. Clinical parameters and ECG markers (r1V1 and SV6 duration and amplitude, QRSV1/QRSV6 duration, V1 and V2 ST amplitude) were independently evaluated for their association to pharmacological test positivity, and a logistic regression model was applied. RESULTS The drug test was positive in 151 (34%) patients. On multivariate logistic regression analysis, age > 45 years, female gender, HR >60 bpm, QRSV1/QRSV6 duration >1 and non-isoelectric pattern in V2 were associated with a positive test. The percentage of patients who tested positive increased according to the presence of the above ECG markers (from 11.3% in the absence to 57.6% in the presence of both factors). During long-term follow-up, the clinical event rate was higher in patients with predictive ECG markers and very low in those without. CONCLUSIONS In our population we confirmed the ability of QRSV1/QRSV6 duration >1 and of a non-isoelectric pattern in V2 to predict a pharmacologically induced type 1 Brugada pattern. Patients with neither of these ECG markers had a rather low event rate during follow-up.
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Affiliation(s)
| | - Federica De Vecchi
- Cardiology Division, Ospedale S. Andrea, Vercelli, Italy; University of Eastern Piedmont, Maggiore della Carità Hospital, Novara, Italy
| | | | - Chiara Devecchi
- Cardiology Division, Ospedale S. Andrea, Vercelli, Italy; University of Eastern Piedmont, Maggiore della Carità Hospital, Novara, Italy
| | - Mario Matta
- Cardiology Division, Ospedale S. Andrea, Vercelli, Italy; Cardiology Division, University of Turin, Turin, Italy
| | | | - Giuseppe Patti
- University of Eastern Piedmont, Maggiore della Carità Hospital, Novara, Italy
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Amir M, Kabo P, Rahma I. Provocative testing using low dose oral flecainide for diagnosis of Brugada syndrome: a report of two cases. Eur Heart J Case Rep 2022; 6:ytac460. [PMID: 36751482 PMCID: PMC9897198 DOI: 10.1093/ehjcr/ytac460] [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: 02/08/2022] [Revised: 03/08/2022] [Accepted: 11/29/2022] [Indexed: 12/14/2022]
Abstract
Background Brugada syndrome (BrS) is a genetic disease characterized by coved ST-segment elevation in the right precordial leads that predispose to life-threatening ventricular tachyarrhythmia. The electrocardiographic signature is dynamic and often concealed but can be unmasked by potent sodium channel blockers such as Flecainide. Some studies have evaluated the effectivity of oral Flecainide 400 mg for provocative testing, but clinical utility of lower dose Flecainide (300 mg) has never been documented. Case summary These two cases illustrate the effectiveness of low dose oral Flecainide to unmask Brugada electrocardiographic pattern. In our patients, diagnostic type 1 electrocardiography started to develop 30 min after drug administration and reached maximal positivity at 3.5-4.5 h. No atrioventricular block or ventricular arrhythmia was observed during the procedures. Discussion A potent sodium channel blocker facilitates marked reduction of the right ventricle epicardial action potential, which creates a transmural voltage dispersion and manifests as an ST elevation in the right precordial leads. Time to positivity was comparably rapid, and time to maximal ST-elevation appeared close to peak plasma level of Flecainide (ranging from 1 to 6 h). Although asymptomatic patients have a low rate of adverse cardiac events, it is crucial to inform patients to avoid various modulators and precipitating factors that could trigger malignant arrhythmias.
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Affiliation(s)
- Muzakkir Amir
- Corresponding author. Tel: +62411-590939, Fax: +62411-590939,
| | - Peter Kabo
- Department of Cardiology and Vascular Medicine, Faculty of Medicine, University of Hasanuddin, Perintis Kemerdekaan Km 11, Makassar, South Sulawesi 90241, Indonesia,Dr. Wahidin Sudirohusodo Hospital, Perintis Kemerdekaan Km 11, Makassar, South Sulawesi 90241, Indonesia
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Morales MA, Piacenti M, Nesti M, Solarino G, Pieragnoli P, Zucchelli G, Del Ry S, Cabiati M, Vozzi F. The BrAID study protocol: integration of machine learning and transcriptomics for brugada syndrome recognition. BMC Cardiovasc Disord 2021; 21:494. [PMID: 34645390 PMCID: PMC8513180 DOI: 10.1186/s12872-021-02280-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/23/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Type 1 Brugada syndrome (BrS) is a hereditary arrhythmogenic disease showing peculiar electrocardiographic (ECG) patterns, characterized by ST-segment elevation in the right precordial leads, and risk of Sudden Cardiac Death (SCD). Furthermore, although various ECG patterns are described in the literature, different individual ECG may show high-grade variability, making the diagnosis problematic. The study aims to develop an innovative system for an accurate diagnosis of Type 1 BrS based on ECG pattern recognition by Machine Learning (ML) models and blood markers analysis trough transcriptomic techniques. METHODS The study is structured in 3 parts: (a) a retrospective study, with the first cohort of 300 anonymized ECG obtained in already diagnosed Type 1 BrS (75 spontaneous, 150 suspected) and 75 from control patients, which will be processed by ML analysis for pattern recognition; (b) a prospective study, with a cohort of 11 patients with spontaneous Type 1 BrS, 11 with drug-induced Type 1 BrS, 11 suspected BrS but negative to Na + channel blockers administration, and 11 controls, enrolled for ECG ML analysis and blood collection for transcriptomics and microvesicles analysis; (c) a validation study, with the third cohort of 100 patients (35 spontaneous and 35 drug-induced BrS, 30 controls) for ML algorithm and biomarkers testing. DISCUSSION The BrAID system will help clinicians improve the diagnosis of Type 1 BrS by using multiple information, reducing the time between ECG recording and final diagnosis, integrating clinical, biochemical and ECG information thus favoring a more effective use of available resources. Trial registration Clinical Trial.gov, NCT04641585. Registered 17 November 2020, https://clinicaltrials.gov/ct2/show/NCT04641585.
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Affiliation(s)
- M A Morales
- CNR Institute of Clinical Physiology, Via Giuseppe Moruzzi 1, 56124, Pisa, Italy
| | - M Piacenti
- Fondazione Toscana Gabriele Monasterio, Via G. Moruzzi 1, Pisa, Italy
| | - M Nesti
- U.O.C. Cardiologia Ospedale San Donato, Via Pietro Nenni 20, Arezzo, Italy
| | - G Solarino
- Azienda Usl Toscana Nord Ovest U.O.C. Cardiologia Ospedale Versilia, SS1 Via Aurelia 335, Lido di Camaiore, Italy
| | - P Pieragnoli
- Azienda Ospedaliera Universitaria Careggi SOD Aritmologia, Largo Brambilla, 3, Firenze, Italy
| | - G Zucchelli
- Azienda Ospedaliero Universitaria Pisana Cardiologia 2 U.O.C. Cisanello, Via Paradisa, 2, Pisa, Italy
| | - S Del Ry
- CNR Institute of Clinical Physiology, Via Giuseppe Moruzzi 1, 56124, Pisa, Italy
| | - M Cabiati
- CNR Institute of Clinical Physiology, Via Giuseppe Moruzzi 1, 56124, Pisa, Italy
| | - F Vozzi
- CNR Institute of Clinical Physiology, Via Giuseppe Moruzzi 1, 56124, Pisa, Italy.
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Hoteit A, Refaat MM. Brugada syndrome masked by complete left bundle branch block. J Cardiovasc Electrophysiol 2021; 32:2791-2792. [PMID: 34411361 DOI: 10.1111/jce.15214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 08/16/2021] [Indexed: 11/29/2022]
Affiliation(s)
- Abbas Hoteit
- Division of Cardiology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
| | - Marwan M Refaat
- Division of Cardiology, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
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Martini N, Testolina M, Toffanin GL, Arancio R, De Mattia L, Cannas S, Morani G, Martini B. Role of Provocable Brugada ECG Pattern in The Correct Risk Stratification for Major Arrhythmic Events. J Clin Med 2021; 10:jcm10051025. [PMID: 33801474 PMCID: PMC7958847 DOI: 10.3390/jcm10051025] [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: 01/11/2021] [Revised: 02/15/2021] [Accepted: 02/23/2021] [Indexed: 11/26/2022] Open
Abstract
The so-called Brugada syndrome (BS), first called precordial early repolarization syndrome (PERS), is characterized by the association of a fascinating electrocardiographic pattern, namely an aspect resembling right bundle branch block with a coved and sometime upsloping ST segment elevation in the precordial leads, and major ventricular arrhythmic events that could rarely lead to sudden death. Its electrogenesis has been related to a conduction delay mostly, but not only, located on the right ventricular outflow tract (RVOT), probably due to a progressive fibrosis of the conduction system. Many tests have been proposed to identify people at risk of sudden death and, among all, ajmaline challenge, thanks to its ability to enhance latent conduction defects, became so popular, even if its role is still controversial as it is neither specific nor sensitive enough to guide further invasive investigations and managements. Interestingly, a type 1 pattern has also been induced in many other cardiac diseases or systemic diseases with a cardiac involvement, such as long QT syndrome (LQTS), arrhythmogenic right ventricular cardiomyopathy (ARVC), hypertrophic cardiomyopathy (HCM) and myotonic dystrophy, without any clear arrhythmic risk profile. Evidence-based studies clearly showed that a positive ajmaline test does not provide any additional information on the risk stratification for major ventricular arrhythmic events on asymptomatic individuals with a non-diagnostic Brugada ECG pattern.
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Affiliation(s)
- Nicolò Martini
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, 35128 Padua, Italy;
| | - Martina Testolina
- Cardiac Unit, Alto Vicentino Hospital, 36014 Santorso, Italy; (M.T.); (G.L.T.); (S.C.); (G.M.)
| | - Gian Luca Toffanin
- Cardiac Unit, Alto Vicentino Hospital, 36014 Santorso, Italy; (M.T.); (G.L.T.); (S.C.); (G.M.)
| | - Rocco Arancio
- Cardiac Unit, Ospedale Umberto Primo, 96100 Siracusa, Italy;
| | | | - Sergio Cannas
- Cardiac Unit, Alto Vicentino Hospital, 36014 Santorso, Italy; (M.T.); (G.L.T.); (S.C.); (G.M.)
| | - Giovanni Morani
- Cardiac Unit, Alto Vicentino Hospital, 36014 Santorso, Italy; (M.T.); (G.L.T.); (S.C.); (G.M.)
| | - Bortolo Martini
- Cardiac Unit, Alto Vicentino Hospital, 36014 Santorso, Italy; (M.T.); (G.L.T.); (S.C.); (G.M.)
- Correspondence:
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Flecainide: Electrophysiological properties, clinical indications, and practical aspects. Pharmacol Res 2019; 148:104443. [PMID: 31493514 DOI: 10.1016/j.phrs.2019.104443] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 08/03/2019] [Accepted: 09/03/2019] [Indexed: 12/19/2022]
Abstract
Over the last 35 years, flecainide proved itself one of the most commonly used arrhythmic drugs, expanding its original indication for ventricular arrhythmias and results nowadays as the cornerstone of the rhythm control strategy in atrial fibrillation management of patients without structural heart disease. While the increased mortality associated with flecainide in the Cardiac Arrhythmia Suppression Trial (CAST) still casts his shadow over flecainide clinical profile, this compound has subsequently demonstrated safe and is now used successfully for a plethora of indications, including pharmacological cardioversion of atrial fibrillation, cathecolaminergic polymorphic ventricular tachycardia, supraventricular tachyarrhythmias and ventricular pre-excitation. Moreover, the recent marketing of a controlled release formulation, along with the intravenous and immediate release formulations, increased the armamentarium to the clinician's disposal while improving patients' compliance. In the present paper, we offer a comprehensive review of the anti-arrhythmic effects of flecainide, detailing its electrophysiological properties, its effects on the conduction system, its clinical use and the major side effects and contraindications in clinical practice.
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Rodríguez -Constaín JS, López-Garzón NA, Navia-Amézquita CA, Mora-Obando DL, Dueñas-Cuellar RA. Síndrome de Brugada. Aspectos fisiopatológicos, clínicos y su asociación con enfermedades infecciosas. IATREIA 2019. [DOI: 10.17533/udea.iatreia.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
El síndrome de Brugada (SBr) es una enfermedad cardiaca no estructural que afecta los canales iónicos cardiacos, caracterizado por manifestaciones clínicas como arritmias, taquicardia, síncope y muerte súbita, entre otras. Su diagnóstico es netamente electrocardiográfico, con un patrón altamente sugestivo pero no patognomónico, por lo que existen diagnósticos diferenciales desde el punto de vista electrocardiográfico.Existen tres patrones electrocardiográficos en los pacientes con SBr, de los cuales el tipo I es el patrón más característico. Actualmente, múltiples genes se han relacionado con la presentación de este síndrome, entre los cuales se destaca el gen SCN5A, el más descrito en la literatura. Se conoce que este síndrome es más frecuente en el género masculino; sin embargo, no existen estudios epidemiológicos en Latinoamérica que lo confirmen. Pese a que la investigación alrededor de los mecanismos causales del síndrome ha avanzado, existen varias cuestiones sin resolver, como su desenmascaramiento por los signos que producen algunas enfermedades infecciosas causadas principalmente por virus. Por lo tanto, dada la relevancia clínica del tema para el médico general y para el especialista, el objetivo de esta revisión es describir no solo aspectos fisiopatológicos y clínicos de la enfermedad, sino también resaltar casos de pacientes con enfermedades infecciosas quienes posteriormente han sido diagnosticados con el síndrome de Brugada.
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de Oliveira Neto NR, de Oliveira WS, Mastrocola F, Sacilotto L. Brugada phenocopy: Mechanisms, diagnosis, and implications. J Electrocardiol 2019; 55:45-50. [DOI: 10.1016/j.jelectrocard.2019.04.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/08/2019] [Accepted: 04/30/2019] [Indexed: 02/06/2023]
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Hohmann S, Rudic B, Konrad T, Duncker D, König T, Tülümen E, Rostock T, Borggrefe M, Veltmann C. Systematic ajmaline challenge in patients with long QT 3 syndrome caused by the most common mutation: a multicentre study. Europace 2018; 19:1723-1729. [PMID: 27915266 DOI: 10.1093/europace/euw214] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/20/2016] [Indexed: 12/19/2022] Open
Abstract
Aims Overlap syndromes of long QT 3 syndrome (LQT3) and the Brugada syndrome (BrS) have been reported. Identification of patients with an overlapping phenotype is crucial before initiation of Class I antiarrhythmic drugs for LQT3. Aim of the present study was to elucidate the yield of ajmaline challenge in unmasking the Brugada phenotype in patients with LQT3 caused by the most common mutation, SCN5A-E1784K. Methods and results Consecutive families in tertiary referral centres diagnosed with LQT3 caused by SCN5A-E1784K were included in the study. Besides routine clinical work-up, ajmaline challenge was performed after informed consent. A total of 23 subjects (11 female, mean age 27 ± 14 years) from 4 unrelated families with a family history of sudden cardiac death and familial diagnosis of the SCN5A-E1784K mutation underwent ajmaline challenge and genetic testing. Sixteen subjects (9 female) were found to be heterozygous carriers of SCN5A-E1784K. Ajmaline challenge was positive in 12 out of the 16 (75%) mutation carriers, but negative in all non-carriers. Following ajmaline, a significant shortening of the rate-corrected JT (JTc) interval was observed in mutation carriers. The baseline JTc interval was significantly longer in mutation carriers with a positive ajmaline challenge compared with those with a negative one. Conclusion Overlap of LQT3 and BrS in patients carrying the most common mutation is high. Therefore, ajmaline challenge represents an important step to rule out potential BrS overlap in these patients before starting sodium channel blockers for the beneficial effect of QT shortening in LQT3.
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Affiliation(s)
- Stephan Hohmann
- Department of Cardiology and Angiology, Rhythmology and Electrophysiology, Hannover Medical School, Carl-Neuberg-Str. 1, Hannover 30625, Germany
| | - Boris Rudic
- 1st Department of Medicine-Cardiology, University Medical Centre Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim 68167, Mannheim, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Mannheim, Germany
| | - Torsten Konrad
- Center of Cardiology, Clinic of Cardiology II/Electrophysiology, Johannes Gutenberg University Mainz, Langenbeckstr. 1, Mainz 55131, Germany
| | - David Duncker
- Department of Cardiology and Angiology, Rhythmology and Electrophysiology, Hannover Medical School, Carl-Neuberg-Str. 1, Hannover 30625, Germany
| | - Thorben König
- Department of Cardiology and Angiology, Rhythmology and Electrophysiology, Hannover Medical School, Carl-Neuberg-Str. 1, Hannover 30625, Germany
| | - Erol Tülümen
- 1st Department of Medicine-Cardiology, University Medical Centre Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim 68167, Mannheim, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Mannheim, Germany
| | - Thomas Rostock
- Center of Cardiology, Clinic of Cardiology II/Electrophysiology, Johannes Gutenberg University Mainz, Langenbeckstr. 1, Mainz 55131, Germany
| | - Martin Borggrefe
- 1st Department of Medicine-Cardiology, University Medical Centre Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim 68167, Mannheim, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, Mannheim, Germany
| | - Christian Veltmann
- Department of Cardiology and Angiology, Rhythmology and Electrophysiology, Hannover Medical School, Carl-Neuberg-Str. 1, Hannover 30625, Germany
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Ueoka A, Morita H, Watanabe A, Morimoto Y, Kawada S, Tachibana M, Miyamoto M, Nakagawa K, Nishii N, Ito H. Prognostic Significance of the Sodium Channel Blocker Test in Patients With Brugada Syndrome. J Am Heart Assoc 2018; 7:JAHA.118.008617. [PMID: 29748178 PMCID: PMC6015319 DOI: 10.1161/jaha.118.008617] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Background A drug provocation test using a sodium channel blocker (SCB) can unmask a type 1 ECG pattern in patients with Brugada syndrome. However, the prognostic value of the results of an SCB challenge is limited in patients with non–type 1 ECG. We investigated the associations of future risk for ventricular fibrillation with SCB‐induced ECG changes and ventricular tachyarrhythmias (VTAs). Methods and Results We administered intravenous pilsicainide to 245 consecutive patients with Brugada syndrome (181 patients with spontaneous type 1 ECG, 64 patients with non–type 1 ECG). ECG parameters before and after the test and occurrence of drug‐induced VTAs were evaluated. During a mean follow‐up period of 113±57 months, fatal VTA events occurred in 31 patients (sudden death: n=3, ventricular tachycardia/ventricular fibrillation: n=28). Symptomatic patients and spontaneous type 1 ECG were associated with future fatal arrhythmic events. Univariable analysis of ECG parameters after the test showed that long PQ and QRS intervals, high ST level, and SCB‐induced VTAs were associated with later VTA events during follow‐up. Multivariable analysis showed that symptomatic patients, high ST level (V1) ≥0.3 mV after the test, and SCB‐induced VTAs were independent predictors for future fatal arrhythmic events (hazard ratios: 3.28, 2.80, and 3.62, 95% confidence intervals: 1.54–7.47, 1.32–6.35, and 1.64–7.75, respectively; P<0.05). Conclusions SCB‐induced VTAs and ST‐segment augmentation are associated with an increased risk of the development of ventricular tachycardia/ventricular fibrillation events during follow‐up in patients with Brugada syndrome.
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Affiliation(s)
- Akira Ueoka
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Hiroshi Morita
- Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Atsuyuki Watanabe
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Yoshimasa Morimoto
- 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
| | - Motomi Tachibana
- 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
| | - 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
| | - Hiroshi Ito
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama, Japan
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SCN5A mutation type and topology are associated with the risk of ventricular arrhythmia by sodium channel blockers. Int J Cardiol 2018; 266:128-132. [PMID: 29709244 DOI: 10.1016/j.ijcard.2017.09.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/25/2017] [Accepted: 09/07/2017] [Indexed: 11/21/2022]
Abstract
BACKGROUND Ventricular fibrillation in patients with Brugada syndrome (BrS) is often initiated by premature ventricular contractions (PVCs). Presence of SCN5A mutation increases the risk of PVCs upon exposure to sodium channel blockers (SCB) in patients with baseline type-1 ECG. In patients without baseline type-1 ECG, however, the effect of SCN5A mutation on the risk of SCB-induced arrhythmia is unknown. We aimed to establish whether presence/absence, type, and topology of SCN5A mutation correlates with PVC occurrence during ajmaline infusion. METHODS AND RESULTS We investigated 416 patients without baseline type-1 ECG who underwent ajmaline testing and SCN5A mutation analysis. A SCN5A mutation was identified in 88 patients (S+). Ajmaline-induced PVCs occurred more often in patients with non-missense mutations (Snon-missense) or missense mutations in transmembrane or pore regions of SCN5A-encoded channel protein (Smissense-TP) than patients with missense mutations in intra-/extracellular channel regions (Smissense-IE) and patients without SCN5A mutation (S-) (29%, 24%, 9%, and 3%, respectively; P<0.001). The proportion of patients with ajmaline-induced BrS was similar in different mutation groups but lower in S- (71% Snon-missense, 63% Smissense-TP, 70% Smissense-IE, and 34% S-; P<0.001). Logistic regression indicated Snon-missense and Smissense-TP as predictors of ajmaline-induced PVCs. CONCLUSIONS SCN5A mutation is associated with an increased risk of drug-induced ventricular arrhythmia in patients without baseline type-1 ECG. In particular, Snon-missense and Smissense-TP are at high risk.
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Salvage SC, Chandrasekharan KH, Jeevaratnam K, Dulhunty AF, Thompson AJ, Jackson AP, Huang CL. Multiple targets for flecainide action: implications for cardiac arrhythmogenesis. Br J Pharmacol 2018; 175:1260-1278. [PMID: 28369767 PMCID: PMC5866987 DOI: 10.1111/bph.13807] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/27/2017] [Accepted: 03/29/2017] [Indexed: 12/19/2022] Open
Abstract
Flecainide suppresses cardiac tachyarrhythmias including paroxysmal atrial fibrillation, supraventricular tachycardia and arrhythmic long QT syndromes (LQTS), as well as the Ca2+ -mediated, catecholaminergic polymorphic ventricular tachycardia (CPVT). However, flecainide can also exert pro-arrhythmic effects most notably following myocardial infarction and when used to diagnose Brugada syndrome (BrS). These divergent actions result from its physiological and pharmacological actions at multiple, interacting levels of cellular organization. These were studied in murine genetic models with modified Nav channel or intracellular ryanodine receptor (RyR2)-Ca2+ channel function. Flecainide accesses its transmembrane Nav 1.5 channel binding site during activated, open, states producing a use-dependent antagonism. Closing either activation or inactivation gates traps flecainide within the pore. An early peak INa related to activation of Nav channels followed by rapid de-activation, drives action potential (AP) upstrokes and their propagation. This is diminished in pro-arrhythmic conditions reflecting loss of function of Nav 1.5 channels, such as BrS, accordingly exacerbated by flecainide challenge. Contrastingly, pro-arrhythmic effects attributed to prolonged AP recovery by abnormal late INaL following gain-of-function modifications of Nav 1.5 channels in LQTS3 are reduced by flecainide. Anti-arrhythmic effects of flecainide that reduce triggering in CPVT models mediated by sarcoplasmic reticular Ca2+ release could arise from its primary actions on Nav channels indirectly decreasing [Ca2+ ]i through a reduced [Na+ ]i and/or direct open-state RyR2-Ca2+ channel antagonism. The consequent [Ca2+ ]i alterations could also modify AP propagation velocity and therefore arrhythmic substrate through its actions on Nav 1.5 channel function. This is consistent with the paradoxical differences between flecainide actions upon Na+ currents, AP conduction and arrhythmogenesis under circumstances of normal and increased RyR2 function. LINKED ARTICLES This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.
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Affiliation(s)
- Samantha C Salvage
- Department of BiochemistryUniversity of CambridgeCambridgeUK
- Physiological LaboratoryUniversity of CambridgeCambridgeUK
| | | | - Kamalan Jeevaratnam
- Faculty of Health and Medical SciencesUniversity of SurreyGuildfordUK
- School of MedicinePerdana University – Royal College of Surgeons IrelandSerdangSelangor Darul EhsanMalaysia
| | - Angela F Dulhunty
- Muscle Research Group, Eccles Institute of Neuroscience, John Curtin School of Medical ResearchAustralian National UniversityActonAustralia
| | | | | | - Christopher L‐H Huang
- Department of BiochemistryUniversity of CambridgeCambridgeUK
- Physiological LaboratoryUniversity of CambridgeCambridgeUK
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Abstract
Brugada syndrome (BrS) is an autosomal dominant inherited channelopathy. It is associated with a typical pattern of ST-segment elevation in the precordial leads V1-V3 and potentially lethal ventricular arrhythmias in otherwise healthy patients. It is frequently seen in young Asian males, in whom it has previously been described as sudden unexplained nocturnal death syndrome. Although it typically presents in young adults, it is also known to present in children and infants, especially in the presence of fever. Our understanding of the genetic pathogenesis and management of BrS has grown substantially considering that it has only been 24 years since its first description as a unique clinical entity. However, there remains much to be learned, especially in the pediatric population. This review aims to discuss the epidemiology, genetics, and pathogenesis of BrS. We will also discuss established standards and new innovations in the diagnosis, prognostication, risk stratification, and management of BrS. Literature search was run on the National Center for Biotechnology Information's website, using the Medical Subject Headings (MeSH) database with the search term "Brugada Syndrome" (MeSH), and was run on the PubMed database using the age filter (birth-18 years), yielding 334 results. The abstracts of all these articles were studied, and the articles were categorized and organized. Articles of relevance were read in full. As and where applicable, relevant references and citations from the primary articles were further explored and read in full.
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Affiliation(s)
- Shashank P Behere
- Nemours Cardiac Center, Nemours/Alfred I duPont Hospital for Children, Wilmington, DE, USA
| | - Steven N Weindling
- The Pediatric Specialty Clinic, Overland Park Regional Medical Center, Overland Park, KS 66215, USA
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Poli S, Toniolo M, Maiani M, Zanuttini D, Rebellato L, Vendramin I, Dametto E, Bernardi G, Bassi F, Napolitano C, Livi U, Proclemer A. Management of untreatable ventricular arrhythmias during pharmacologic challenges with sodium channel blockers for suspected Brugada syndrome. Europace 2017; 20:234-242. [DOI: 10.1093/europace/eux092] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Accepted: 03/15/2017] [Indexed: 01/21/2023] Open
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KIM SUNGHWAN, NAM GIBYOUNG, YUN SUNGCHEOL, CHOI HYUNGOH, CHOI KEEJOON, JOUNG BOYOUNG, PAK HUINAM, LEE MOONHYOUNG, KIM SUNGSOON, PARK SEUNGJUNG, ON YOUNGKEUN, KIM JUNESOO, OH ILYOUNG, CHOI EUEKEUN, OH SEIL, CHOI YUNSHIK, CHOI JONGIL, PARK SANGWEON, KIM YOUNGHOON, OH YONGSEOG, LEE MANYOUNG, LIM HONGEUY, LEE YOUNGSOO, CHO YONGKEUN, KIM JUN, RHEE KYOUNGSUK, LEE DONGIL, CHO DAEKYOUNG, KIM YOUHO. Variants of Brugada Syndrome and Early Repolarization Syndrome: An Expanded Concept of J-Wave Syndrome. Pacing Clin Electrophysiol 2017; 40:162-174. [DOI: 10.1111/pace.13000] [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: 04/25/2016] [Revised: 10/11/2016] [Accepted: 10/25/2016] [Indexed: 11/29/2022]
Affiliation(s)
- SUNG-HWAN KIM
- Department of Internal Medicine, College of Medicine, Seoul St. Mary's Hospital; The Catholic University of Korea; Seoul Korea
| | - GI-BYOUNG NAM
- Department of Internal Medicine, College of Medicine, Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
| | - SUNG-CHEOL YUN
- Department of Internal Medicine, College of Medicine, Severance Cardiovascular Hospital; Yonsei University; Seoul Korea
| | - HYUNG OH CHOI
- Department of Internal Medicine, College of Medicine, Severance Cardiovascular Hospital; Yonsei University; Seoul Korea
| | - KEE-JOON CHOI
- Department of Internal Medicine, College of Medicine, Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
| | - BOYOUNG JOUNG
- Department of Internal Medicine, College of Medicine, Severance Cardiovascular Hospital; Yonsei University; Seoul Korea
| | - HUI-NAM PAK
- Department of Internal Medicine, College of Medicine, Severance Cardiovascular Hospital; Yonsei University; Seoul Korea
| | - MOON-HYOUNG LEE
- Department of Internal Medicine, College of Medicine, Severance Cardiovascular Hospital; Yonsei University; Seoul Korea
| | - SUNG SOON KIM
- Department of Internal Medicine, College of Medicine, Severance Cardiovascular Hospital; Yonsei University; Seoul Korea
| | - SEUNG-JUNG PARK
- Department of Internal Medicine, College of Medicine, Samsung Medical Center; Sungkyunkwan University; Seoul Korea
| | - YOUNG KEUN ON
- Department of Internal Medicine, College of Medicine, Samsung Medical Center; Sungkyunkwan University; Seoul Korea
| | - JUNE SOO KIM
- Department of Internal Medicine, College of Medicine, Samsung Medical Center; Sungkyunkwan University; Seoul Korea
| | - IL-YOUNG OH
- Department of Internal Medicine, College of Medicine; Seoul National University Hospital; Seoul Korea
| | - EUE-KEUN CHOI
- Department of Internal Medicine, College of Medicine; Seoul National University Hospital; Seoul Korea
| | - SEIL OH
- Department of Internal Medicine, College of Medicine; Seoul National University Hospital; Seoul Korea
| | - YUN-SHIK CHOI
- Department of Internal Medicine, College of Medicine; Seoul National University Hospital; Seoul Korea
| | - JONG IL CHOI
- Department of Internal Medicine, College of Medicine; Korea University Anam Hospital; Seoul Korea
| | - SANG WEON PARK
- Department of Internal Medicine, College of Medicine; Korea University Anam Hospital; Seoul Korea
| | - YOUNG-HOON KIM
- Department of Internal Medicine, College of Medicine; Korea University Anam Hospital; Seoul Korea
| | - YONG-SEOG OH
- Department of Internal Medicine, College of Medicine, Seoul St. Mary's Hospital; The Catholic University of Korea; Seoul Korea
| | - MAN YOUNG LEE
- Department of Internal Medicine, College of Medicine, Yeouido St. Mary's Hospital; The Catholic University of Korea; Seoul Korea
| | - HONG EUY LIM
- Department of Internal Medicine, College of Medicine; Korea University Guro Hospital; Seoul Korea
| | - YOUNG-SOO LEE
- Department of Internal Medicine, College of Medicine; Catholic University of Daegu; Daegu Korea
| | - YONGKEUN CHO
- Department of Internal Medicine, College of Medicine; Kyungpook National University Hospital; Daegu Korea
| | - JUN KIM
- Department of Internal Medicine, College of Medicine, Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
| | - KYOUNG-SUK RHEE
- Department of Internal Medicine, College of Medicine; Chonbuk National University Hospital; Jeonju Korea
| | - DONG-IL LEE
- Department of Internal Medicine, College of Medicine; Hanseo Hospital; Busan Korea
| | - DAE KYOUNG CHO
- Department of Internal Medicine, College of Medicine; Hanmaeum General Hospital; Jeju Korea
| | - YOU-HO KIM
- Department of Internal Medicine, College of Medicine, Asan Medical Center; University of Ulsan College of Medicine; Seoul Korea
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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Prasad S, Namboodiri N, Thajudheen A, Singh G, Prabhu MA, Abhilash SP, Mohanan Nair KK, Rashid A, Ajit Kumar VK, Tharakan JA. Flecainide challenge test: Predictors of unmasking of type 1 Brugada ECG pattern among those with non-type 1 Brugada ECG pattern. Indian Pacing Electrophysiol J 2016; 16:53-58. [PMID: 27676161 PMCID: PMC5031807 DOI: 10.1016/j.ipej.2016.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 06/18/2016] [Indexed: 11/18/2022] Open
Abstract
Background Many subjects in community have non-type 1 Brugada pattern ECG with atypical symptoms, relevance of which is not clear. Provocative tests to unmask type 1 Brugada pattern in these patients would help in diagnosing Brugada Syndrome. However sensitivity and specificity of provocating drugs are variable. Methods We studied 29 patients referred to our institute with clinical presentation suggestive but not diagnostic of Brugada or with non-Type 1 Brugada pattern ECG. Flecainide Challenge Test (FCT) was done in these patients (IV Flecainide test in 4 patients and Oral Flecainide in 25 patients). Resting 12-lead ECG with standard precordial leads and ECG with precordial leads placed 1 Intercostal space above were performed after flecainide administration every 5 min for first 30 min and every 30 min thereafter until ECG became normal or upto 6 h. The positivity was defined as inducible Type 1 Brugada pattern in atleast 2 right sided leads. Result Median age was 35(range = 5–65) years. In 16 (55%) patients the Type 1 Brugada pattern was unmasked. There were no episodes of major AV block, atrial or ventricular tachyarrhythmia. Three groups were considered for analysis: Group 1(n = 9) – FCT Positive among patients with non-type 1 Brugada ECG pattern, Group 2(n = 4) – FCT Negative among the patients with non-type 1 Brugada ECG pattern, and Group 3(n = 7) – FCT Positive among patients with no spontaneous Brugada ECG pattern. Binary logistic regression analysis found that family h/o SCD was predictive of FCT positivity in Group 1 (Odd’s ratio 21, 95% Confidence interval 1.04 to 698.83, p = 0.004). Conclusion Oral flecainide is useful and safe for unmasking of Type I Brugada pattern. In our study, among the many variables studied, family history of sudden cardiac death was the only predictor of flecainide test positivity among those with non-Type 1 Brugada pattern.
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Affiliation(s)
- Srinivasa Prasad
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India
| | - Narayanan Namboodiri
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India.
| | - Anees Thajudheen
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India
| | - Gurbhej Singh
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India
| | - Mukund A Prabhu
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India
| | - S P Abhilash
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India
| | | | - Aamir Rashid
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India
| | - V K Ajit Kumar
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India
| | - Jaganmohan A Tharakan
- Department of Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, India
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18
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Curcio A, Mazzanti A, Bloise R, Monteforte N, Indolfi C, Priori SG, Napolitano C. Clinical Presentation and Outcome of Brugada Syndrome Diagnosed With the New 2013 Criteria. J Cardiovasc Electrophysiol 2016; 27:937-43. [PMID: 27098113 DOI: 10.1111/jce.12997] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/21/2016] [Accepted: 04/14/2016] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The 2013 HRS/EHRA/APHRS consensus statement recommends the use of V1 and V2 leads recorded in the second and third intercostal spaces (High-ICS) for diagnosis of Brugada syndrome (BrS) creating a new category of patients discovered only with modified leads. The clinical presentation and the arrhythmic risk in these patients are ill defined. This study was aimed at assessing the role of High-ICS in the analysis of BrS and the clinical profile of the patients diagnosed only when ECG leads are moved to upper intercostal spaces. METHODS AND RESULTS We searched our Brugada syndrome registry and identified 300 subjects (age 36 ± 13 years), without a diagnostic coved ST-segment elevation in conventional V1 -V3 leads, both at baseline and after provocative drug challenge. Sixty-four subjects (21.3%, mean age at last follow-up 42 ± 11 years) were diagnosed with High-ICS. Diagnosis was possible at baseline only in 4 subjects while in 60 it was made after drug challenge with sodium channel blockers. Three subjects (4.7%) with spontaneous abnormal ECG experienced cardiac events with an annual event rate (0.11%) superimposable to that of the low risk category of BrS diagnosed in standard leads. CONCLUSION This study demonstrates that the use of new diagnostic criteria for BrS allows increasing the diagnostic yield by 20% and that the arrhythmic risk is low when BrS can be established only in High-ICS. We also show that the prognostic value of spontaneous ECG pattern is confirmed in this subgroup.
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Affiliation(s)
- Antonio Curcio
- Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy
| | - Andrea Mazzanti
- Laboratory of Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Raffaella Bloise
- Laboratory of Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Nicola Monteforte
- Laboratory of Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Ciro Indolfi
- Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy.,U.R.T.-C.N.R, Catanzaro, Italy
| | - Silvia G Priori
- Laboratory of Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy.,Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Carlo Napolitano
- Laboratory of Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
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19
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Dobbels B, De Cleen D, Ector J. Ventricular arrhythmia during ajmaline challenge for the Brugada syndrome. Europace 2016; 18:1501-1506. [DOI: 10.1093/europace/euw008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 01/06/2016] [Indexed: 12/25/2022] Open
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20
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Antzelevitch C, Patocskai B. Brugada Syndrome: Clinical, Genetic, Molecular, Cellular, and Ionic Aspects. Curr Probl Cardiol 2016; 41:7-57. [PMID: 26671757 PMCID: PMC4737702 DOI: 10.1016/j.cpcardiol.2015.06.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Brugada syndrome (BrS) is an inherited cardiac arrhythmia syndrome first described as a new clinical entity in 1992. Electrocardiographically characterized by distinct coved type ST segment elevation in the right-precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young adults, and less frequently in infants and children. The electrocardiographic manifestations of BrS are often concealed and may be unmasked or aggravated by sodium channel blockers, a febrile state, vagotonic agents, as well as by tricyclic and tetracyclic antidepressants. An implantable cardioverter defibrillator is the most widely accepted approach to therapy. Pharmacologic therapy is designed to produce an inward shift in the balance of currents active during the early phases of the right ventricular action potential (AP) and can be used to abort electrical storms or as an adjunct or alternative to device therapy when use of an implantable cardioverter defibrillator is not possible. Isoproterenol, cilostazol, and milrinone boost calcium channel current and drugs like quinidine, bepridil, and the Chinese herb extract Wenxin Keli inhibit the transient outward current, acting to diminish the AP notch and thus to suppress the substrate and trigger for ventricular tachycardia or fibrillation. Radiofrequency ablation of the right ventricular outflow tract epicardium of patients with BrS has recently been shown to reduce arrhythmia vulnerability and the electrocardiographic manifestation of the disease, presumably by destroying the cells with more prominent AP notch. This review provides an overview of the clinical, genetic, molecular, and cellular aspects of BrS as well as the approach to therapy.
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Affiliation(s)
| | - Bence Patocskai
- Masonic Medical Research Laboratory, Utica, NY 13501
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
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21
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Affiliation(s)
- Arthur A.M. Wilde
- From the Heart Centre, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (A.A.M.W.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Kingdom of Saudi Arabia (A.A.M.W.); The Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.); and Bangkok Heart Hospital, Bangkok, Thailand (K.N.)
| | - Koonlawee Nademanee
- From the Heart Centre, Department of Clinical and Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands (A.A.M.W.); Princess Al-Jawhara Al-Brahim Centre of Excellence in Research of Hereditary Disorders, Jeddah, Kingdom of Saudi Arabia (A.A.M.W.); The Pacific Rim Electrophysiology Research Institute, Los Angeles, CA (K.N.); and Bangkok Heart Hospital, Bangkok, Thailand (K.N.)
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22
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Viskin S, Rosso R, Friedensohn L, Havakuk O, Wilde AAM. Everybody has Brugada syndrome until proven otherwise? Heart Rhythm 2015; 12:1595-8. [PMID: 25998201 DOI: 10.1016/j.hrthm.2015.04.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Sami Viskin
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Raphael Rosso
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Limor Friedensohn
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ofer Havakuk
- Tel Aviv Sourasky Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Arthur A M Wilde
- Heart Center, Academic Medical Center, Amsterdam, The Netherlands
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Uziębło-Życzkowska B, Gielerak G, Michałkiewicz D. Usefulness of patient's history and non-invasive electrocardiographic parameters in prediction of ajmaline test results in patients with suspected Brugada syndrome. Arch Med Sci 2014; 10:899-912. [PMID: 25395941 PMCID: PMC4223127 DOI: 10.5114/aoms.2013.36928] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 05/26/2012] [Accepted: 09/16/2012] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION The aim of the work was to assess the usefulness of patient's history and non-invasive electrocardiographic parameters in the prediction of ajmaline test results in patients with suspected Brugada syndrome. MATERIAL AND METHODS The study involved a group of 59 patients (37 men) at average age of 31.6 ±12.2 years with suspected concealed form of Brugada syndrome. Pharmacological provocation with intravenous ajmaline administration was performed. The patients were divided into two groups depending on ajmaline test results. Individual and total predictive value for ajmaline test was based on the analysis of medical anamnesis and non-invasive electrocardiographic examination. RESULTS The analysis carried out within the work indicated a special predictive value of 2 parameters which constituted the study inclusion criteria - family history of Brugada syndrome (28.6% vs. 3.8%; p = 0.0477) and occurrence of saddleback electrocardiographic changes in ECG curve (42.9% vs. 0.0%; p = 0.0002). Non-invasive electrocardiographic parameters which showed significant predictive value for ajmaline test were as follows: dispersion of QTc interval (prior to the provocation test 54.43 ±24.77 ms vs. 32.70 ±12.98 ms; p = 0.0005 and during daytime activity 46.81 ±27.16 ms vs. 32.07 ±13.19 ms; p = 0.0198), corrected QT intervals, Tpeak-Tend intervals in particular leads, QTpeak intervals, dispersion of Tpeak-Tend interval assessed from precordial leads (V1-V6) (42.86 ±13.80 ms vs. 26.54 ±11.70 ms; p = 0.001) and J-point elevation in V2 and V3 leads. CONCLUSIONS Both interview and non-invasive electrocardiographic parameters which reflect cardiomyocyte repolarization disorders are of high predictive value in anticipating ajmaline pharmacological provocation results in patients with suspected Brugada syndrome.
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Affiliation(s)
| | - Grzegorz Gielerak
- Department of Cardiology and Internal Diseases, Military Institute of Medicine, Warsaw, Poland
| | - Dariusz Michałkiewicz
- Department of Cardiology and Internal Diseases, Military Institute of Medicine, Warsaw, Poland
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de-Riva-Silva M, Montero-Cabezas JM, Fontenla-Cerezuela A, Salguero-Bodes R, López-Gil M, Arribas-Ynsaurriaga F. Delayed positive response to a flecainide test in a patient with suspected Brugada syndrome: a worrisome finding. REVISTA ESPANOLA DE CARDIOLOGIA (ENGLISH ED.) 2014; 67:674-675. [PMID: 25037552 DOI: 10.1016/j.rec.2014.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 03/26/2014] [Indexed: 06/03/2023]
Affiliation(s)
- Marta de-Riva-Silva
- Unidad de Arritmias y Electrofisiología, Servicio de Cardiología, Hospital 12 de Octubre, Madrid, Spain.
| | - José M Montero-Cabezas
- Unidad de Arritmias y Electrofisiología, Servicio de Cardiología, Hospital 12 de Octubre, Madrid, Spain
| | - Adolfo Fontenla-Cerezuela
- Unidad de Arritmias y Electrofisiología, Servicio de Cardiología, Hospital 12 de Octubre, Madrid, Spain
| | - Rafael Salguero-Bodes
- Unidad de Arritmias y Electrofisiología, Servicio de Cardiología, Hospital 12 de Octubre, Madrid, Spain
| | - María López-Gil
- Unidad de Arritmias y Electrofisiología, Servicio de Cardiología, Hospital 12 de Octubre, Madrid, Spain
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de-Riva-Silva M, Montero-Cabezas JM, Fontenla-Cerezuela A, Salguero-Bodes R, López-Gil M, Arribas-Ynsaurriaga F. Respuesta positiva diferida al test de flecainida en paciente con sospecha de síndrome de Brugada: un hallazgo preocupante. Rev Esp Cardiol 2014. [DOI: 10.1016/j.recesp.2014.03.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Wolpert C, Herrera-Siklody C, Parade U, Strotmann C, Rüb N. [Brugada syndrome]. Herzschrittmacherther Elektrophysiol 2013; 24:209-216. [PMID: 24100621 DOI: 10.1007/s00399-013-0294-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Brugada syndrome is an ion channel disease which is associated with an increased risk of sudden cardiac death. Most probably the pathogenesis of ventricular fibrillation in these patients is a combination of both genetically determined repolarisation abnormalities and conduction delay in the right ventricular epicardium. The highest risk of sudden cardiac death is present in patients who have experienced syncope before, who reveal the pathognomic electrocardiographic changes already at rest and who have inducible ventricular fibrillation. Asymptomatic patients who have the J point elevations only after administration of a sodium channel blocker seem to be at lower risk. Most recently the latest joint consensus recommendations of the largest societies for diagnostic criteria, indications for genetic testing and therapy have been published.
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Affiliation(s)
- Christian Wolpert
- Klinik für Innere Medizin, Kardiologie, Nephrologie und internistische Intensivmedizin, Klinikum Ludwigsburg, Posilipostraße 4, 71640, Ludwigsburg, Deutschland,
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Nault I, Champagne J. How safe is ajmaline challenge in patients with suspected Brugada syndrome? Heart Rhythm 2013; 10:1875-6. [PMID: 24177371 DOI: 10.1016/j.hrthm.2013.10.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Indexed: 10/26/2022]
Affiliation(s)
- Isabelle Nault
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, Canada.
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28
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Conte G, Sieira J, Sarkozy A, de Asmundis C, Di Giovanni G, Chierchia GB, Ciconte G, Levinstein M, Casado-Arroyo R, Baltogiannis G, Saenen J, Saitoh Y, Pappaert G, Brugada P. Life-threatening ventricular arrhythmias during ajmaline challenge in patients with Brugada syndrome: incidence, clinical features, and prognosis. Heart Rhythm 2013; 10:1869-74. [PMID: 24055942 DOI: 10.1016/j.hrthm.2013.09.060] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Sustained ventricular arrhythmias (sVAs), such as polymorphic ventricular tachycardia or ventricular fibrillation, can complicate ajmaline challenge in patients with Brugada syndrome (BS). OBJECTIVE To assess the incidence of life-threatening sVAs during ajmaline administration in a large series of patients with BS. In addition, clinical characteristics as well as prognosis of these patients were evaluated. METHODS All consecutive patients with ajmaline-induced diagnosis of BS were eligible for this study. RESULTS A total of 503 patients were included. Nine (1.8%) patients (44% men; mean age 26 ± 18 years) developed a life-threatening sVA during ajmaline challenge. Three patients (33%)were children, and 2 (22%) patients experienced sVAs refractory to the first external defibrillation. One patient underwent venoarterial extracorporeal membrane oxygenation to restore sinus rhythm. Age at the time of ajmaline challenge was significantly lower in patients with sVAs compared with patients without sVAs (26 ± 18 years vs 41 ± 18 years; P = .01). Moreover, patients with sVAs presented more frequently with sinus node dysfunction compared with patients with normal response to ajmaline (22.2% vs 1.4%; P = .01). After a mean follow-up time of 29 ± 8 months, none of the patients who had developed a sVA during ajmaline challenge died suddenly or developed further life-threatening ventricular arrhythmias. CONCLUSIONS sVA during ajmaline challenge is not a rare event in BS occurring in 9 (1.8%) patients. Despite its challenging acute treatment, the occurrence of ajmaline-induced sVAs in patients with BS might not identify a category at higher risk for further arrhythmic events.
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Affiliation(s)
- Giulio Conte
- Heart Rhythm Management Centre, UZ Brussel-VUB, Brussels, Belgium.
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Hashemi A, Shahrzad S, Shahrzad S, Saber S, Taban S, Aslani A, Emkanjoo Z. Positive Brugada challenge test in V1 R-V3 R as a predictor of malignant prognosis in Brugada patients. Ann Noninvasive Electrocardiol 2013; 18:421-6. [PMID: 24047485 DOI: 10.1111/anec.12055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The Brugada syndrome is a heterogeneous genetic disease that predisposes to life-threatening ventricular tachyarrhythmias and sudden cardiac death (SCD). The only proven way to prolong the survival of patients with Brugada syndrome is to implant an implantable cardioverter-defibrillator (ICD). This should be implanted for high-risk patients only. METHOD The patients with type 2 or 3 Brugada ECG pattern were selected for the study. We evaluated 126 patients with Brugada type ECG patterns. Nineteen patients had positive response. Those who had positive result in right side located leads had poorer prognosis. CONCLUSION Positive flecainide challenge test in right side located pericordial leads can be used as a predictor of poor prognosis in Brugada patients. This can be evaluated in another research for its role in the implantation of ICD. Also, the oral flecainide is not sensitive enough to rule out the presence of Brugada syndrome and it should not be trusted as a screening test for suspected cases.
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Affiliation(s)
- Arash Hashemi
- Cardiac Electrophysiology Research Center, Rajaei Cardiovascular Research and Medical Center, Tehran University of Medical Sciences, Tehran, Iran
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King JH, Huang CLH, Fraser JA. Determinants of myocardial conduction velocity: implications for arrhythmogenesis. Front Physiol 2013; 4:154. [PMID: 23825462 PMCID: PMC3695374 DOI: 10.3389/fphys.2013.00154] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/10/2013] [Indexed: 12/19/2022] Open
Abstract
Slowed myocardial conduction velocity (θ) is associated with an increased risk of re-entrant excitation, predisposing to cardiac arrhythmia. θ is determined by the ion channel and physical properties of cardiac myocytes and by their interconnections. Thus, θ is closely related to the maximum rate of action potential (AP) depolarization [(dV/dt)max], as determined by the fast Na+ current (INa); the axial resistance (ra) to local circuit current flow between cells; their membrane capacitances (cm); and to the geometrical relationship between successive myocytes within cardiac tissue. These determinants are altered by a wide range of pathophysiological conditions. Firstly, INa is reduced by the impaired Na+ channel function that arises clinically during heart failure, ischemia, tachycardia, and following treatment with class I antiarrhythmic drugs. Such reductions also arise as a consequence of mutations in SCN5A such as those occurring in Lenègre disease, Brugada syndrome (BrS), sick sinus syndrome, and atrial fibrillation (AF). Secondly, ra, may be increased due to gap junction decoupling following ischemia, ventricular hypertrophy, and heart failure, or as a result of mutations in CJA5 found in idiopathic AF and atrial standstill. Finally, either ra or cm could potentially be altered by fibrotic change through the resultant decoupling of myocyte–myocyte connections and coupling of myocytes with fibroblasts. Such changes are observed in myocardial infarction and cardiomyopathy or following mutations in MHC403 and SCN5A resulting in hypertrophic cardiomyopathy (HCM) or Lenègre disease, respectively. This review defines and quantifies the determinants of θ and summarizes experimental evidence that links changes in these determinants with reduced myocardial θ and arrhythmogenesis. It thereby identifies the diverse pathophysiological conditions in which abnormal θ may contribute to arrhythmia.
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Affiliation(s)
- James H King
- Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge Cambridge, UK
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Arnalsteen-Dassonvalle E, Hermida JS, Kubala M, Six I, Quenum S, Leborgne L, Jarry G. Ajmaline challenge for the diagnosis of Brugada syndrome: Which protocol? Arch Cardiovasc Dis 2010; 103:570-8. [DOI: 10.1016/j.acvd.2010.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 10/06/2010] [Accepted: 10/07/2010] [Indexed: 11/16/2022]
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Veltmann C, Wolpert C, Sacher F, Mabo P, Schimpf R, Streitner F, Brade J, Kyndt F, Kuschyk J, Le Marec H, Borggrefe M, Probst V. Response to intravenous ajmaline: a retrospective analysis of 677 ajmaline challenges. Europace 2009; 11:1345-52. [PMID: 19589796 DOI: 10.1093/europace/eup189] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS The diagnostic type I ECG in Brugada syndrome (BS) is often concealed and fluctuates between the diagnostic and non-diagnostic pattern. Challenge with intravenous ajmaline is used to unmask the diagnostic Brugada ECG. The aim of this study was to evaluate the safety of the test and to identify predictors for the response to an intravenous ajmaline challenge. METHODS AND RESULTS In four tertiary referral centres, 677 consecutive patients underwent an intravenous ajmaline challenge for diagnosis or exclusion of BS in accordance with the recommendations of the Brugada consensus conferences. Two hundred and sixty-two ajmaline challenges (39%) were positive. Male gender, familial BS, sudden cardiac arrest (SCA), first-degree AV-block, basal saddleback type ECG, and basal right bundle branch block were identified as predictors for a positive ajmaline challenge. A predictor for negative ajmaline test was the absence of ST-segment elevation at baseline. Six of 12 patients who had experienced SCA, and five of 25 patients with a familial sudden death exhibited a positive response to ajmaline. Only one patient (0.15%) developed sustained ventricular tachyarrhythmias (ventricular fibrillation) during ajmaline challenge, which was terminated by a single external defibrillator shock. CONCLUSION Ajmaline challenge is a safe procedure to unmask the electrocardiographic pattern of BS. Electrocardiographic and clinical parameters were identified to predict patients' response to ajmaline. The results of this study guide the clinician in which setting an ajmaline challenge is an appropriate diagnostic step.
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Affiliation(s)
- Christian Veltmann
- 11st Department of Medicine-Cardiology, University Hospital Mannheim, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
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Postema PG, Wolpert C, Amin AS, Probst V, Borggrefe M, Roden DM, Priori SG, Tan HL, Hiraoka M, Brugada J, Wilde AAM. Drugs and Brugada syndrome patients: review of the literature, recommendations, and an up-to-date website (www.brugadadrugs.org). Heart Rhythm 2009; 6:1335-41. [PMID: 19716089 DOI: 10.1016/j.hrthm.2009.07.002] [Citation(s) in RCA: 247] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 07/03/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND Worldwide, the Brugada syndrome has been recognized as an important cause of sudden cardiac death in individuals at a relatively young age. Importantly, many drugs have been reported to induce the characteristic Brugada syndrome-linked ECG abnormalities and/or (fatal) ventricular tachyarrhythmias. OBJECTIVE The purpose of this study was to review the literature on the use of drugs in Brugada syndrome patients, to make recommendations based on the literature and on expert opinion regarding drug safety, and to ensure worldwide online and up-to-date availability of this information to all physicians who treat Brugada syndrome patients. METHODS We performed an extensive review of the literature, formed an international expert panel to produce a consensus recommendation to each drug, and initiated a website (www.brugadadrugs.org). RESULTS The literature search yielded 506 reports for consideration. Drugs were categorized into one of four categories: (1) drugs to be avoided (n = 18); (2) drugs preferably avoided (n = 23); (3) antiarrhythmic drugs (n = 4); and (4) diagnostic drugs (n = 4). Level of evidence for most associations was C (only consensus opinion of experts, case studies, or standard-of-care) as there are no randomized studies and few nonrandomized studies in Brugada syndrome patients. CONCLUSION Many drugs have been associated with adverse events in Brugada syndrome patients. We have initiated a website (www.brugadadrugs.org) to ensure worldwide availability of information on safe drug use in Brugada syndrome patients.
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Affiliation(s)
- Pieter G Postema
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Gjesdal K. Non-investigational antiarrhythmic drugs: long-term use and limitations. Expert Opin Drug Saf 2009; 8:345-55. [DOI: 10.1517/14740330902927647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Significance of QRS prolongation during diagnostic ajmaline test in patients with suspected Brugada syndrome. Heart Rhythm 2009; 6:625-31. [DOI: 10.1016/j.hrthm.2009.01.038] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Accepted: 01/31/2009] [Indexed: 11/22/2022]
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Differential effects of cardiac sodium channel mutations on initiation of ventricular arrhythmias in patients with Brugada syndrome. Heart Rhythm 2009; 6:487-92. [DOI: 10.1016/j.hrthm.2009.01.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Accepted: 01/26/2009] [Indexed: 11/23/2022]
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Evain S, Briec F, Kyndt F, Schott J, Lande G, Albuisson J, Abbey S, Le Marec H, Probst V. Sodium channel blocker tests allow a clear distinction of electrophysiological characteristics and prognosis in patients with a type 2 or 3 Brugada electrocardiogram pattern. Heart Rhythm 2008; 5:1561-4. [DOI: 10.1016/j.hrthm.2008.08.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 08/23/2008] [Indexed: 10/21/2022]
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40
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Barajas-Martínez HM, Hu D, Cordeiro JM, Wu Y, Kovacs RJ, Meltser H, Kui H, Elena B, Brugada R, Antzelevitch C, Dumaine R. Lidocaine-induced Brugada syndrome phenotype linked to a novel double mutation in the cardiac sodium channel. Circ Res 2008; 103:396-404. [PMID: 18599870 DOI: 10.1161/circresaha.108.172619] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Brugada syndrome has been linked to mutations in SCN5A. Agents that dissociate slowly from the sodium channel such as flecainide and ajmaline unmask the Brugada syndrome electrocardiogram and precipitate ventricular tachycardia/fibrillation. Lidocaine, an agent with rapid dissociation kinetics, has previously been shown to exert no effect in patients with Brugada syndrome. We characterized a novel double mutation of SCN5A (V232I in DI-S4+L1308F in DIII-S4) identified in a rare case of lidocaine (1 mg/kg)-induced Brugada syndrome. We studied lidocaine blockade of I(Na) generated by wild-type and V232I+L1308F mutant cardiac sodium channels expressed in mammalian TSA201 cells using patch clamp techniques. Despite no significant difference in steady-state gating parameters between V232I+L1308F and wild-type sodium currents at baseline, use-dependent inhibition of I(Na) by lidocaine was more pronounced in V232I+L1308F versus wild-type (73.0+/-0.1% versus 18.23+/-0.04% at 10 micromol/L measured at 10 Hz, respectively). A dose of 10 micromol/L lidocaine also caused a more negative shift of steady-state inactivation in V232I+L1308F versus wild-type (-14.1+/-0.3 mV and -4.8+/-0.3 mV, respectively). The individual mutations produced a much less accentuated effect. We report the first case of lidocaine-induced Brugada electrocardiogram phenotype. The double mutation in SCN5A, V232I, and L1308F alters the affinity of the cardiac sodium channel for lidocaine such that the drug assumes Class IC characteristics with potent use-dependent block of the sodium channel. Our results demonstrate an additive effect of the 2 missense mutations to sensitize the sodium channel to lidocaine. These findings suggest caution when treating patients carrying such genetic variations with Class I antiarrhythmic drugs.
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Cordeiro JM, Mazza M, Goodrow R, Ulahannan N, Antzelevitch C, Di Diego JM. Functionally distinct sodium channels in ventricular epicardial and endocardial cells contribute to a greater sensitivity of the epicardium to electrical depression. Am J Physiol Heart Circ Physiol 2008; 295:H154-62. [PMID: 18456729 DOI: 10.1152/ajpheart.01327.2007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A greater depression of the action potential (AP) of the ventricular epicardium (Epi) versus endocardium (Endo) is readily observed in experimental models of acute ischemia and Brugada syndrome. Endo and Epi differences in transient outward K(+) current and/or ATP-sensitive K(+) channel current are believed to contribute to the differential response. The present study tested the hypothesis that the greater sensitivity of Epi is due in part to its functionally distinct early fast Na(+) current (I(Na)). APs were recorded from isolated Epi and Endo tissue slices and coronary-perfused wedge preparations before and after exposures to elevated extracellular K(+) concentration ([K(+)](o); 6-12 mM). I(Na) was recorded from Epi and Endo myocytes using whole cell patch-clamp techniques. In tissue slices, increasing [K(+)](o) to 12 mM reduced V(max) to 51.1 +/- 5.3% and 26.8 +/- 9.6% of control in Endo (n = 9) and Epi (n = 14), respectively (P < 0.05). In wedge preparations (n = 12), the increase in [K(+)](o) caused selective depression of Epi APs and transmural conduction slowing and block. I(Na) density was not significantly different between Epi (n = 14) and Endo (n = 15) cells, but Epi cells displayed a more negative half-inactivation voltage [-83.6 +/- 0.1 and -75.5 +/- 0.3 mV for Epi (n = 16) and Endo (n = 16), respectively, P < 0.05]. Our data suggest that reduced I(Na) availability in ventricular Epi may contribute to its greater sensitivity to electrical depression and thus may contribute to the R-ST segment changes observed under a variety of clinical conditions including acute myocardial ischemia, severe hyperkalemia, and Brugada syndrome.
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Affiliation(s)
- J M Cordeiro
- Masonic Medical Research Laboratory, Utica, NY 13504, USA
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Zhu ZI, Clancy CE. Genetic mutations and arrhythmia: simulation from DNA to electrocardiogram. J Electrocardiol 2008; 40:S47-50. [PMID: 17993328 DOI: 10.1016/j.jelectrocard.2007.05.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 05/14/2007] [Indexed: 12/20/2022]
Abstract
In the past two decades, mutations in cardiac ion channels have been shown to underlie a number of rare inherited cardiac arrhythmias. Defects in cardiac Na(+) channels can disrupt channel gating and cause electrical abnormalities that increase susceptibility to cardiac arrhythmia. Dozens of mutations have been identified in the gene SCN5A, which encodes the alpha subunit of the cardiac Na(+) channel, and have been causally linked to a wide spectrum of cardiac arrhythmic disorders. An important step in understanding genetically based arrhythmias is to clarify the relationship between molecular defects and the disruption of the delicate balance of dynamic interactions at the cell, tissue, and organ levels. Here, we provide an overview of cardiac Na(+) channel mutations that are associated with inherited arrhythmia syndromes. We also address pros and cons of current methodologies used to understand how specific genetic defects disrupt channel-gating kinetics and underlie cardiac arrhythmia. Finally, we discuss effects of mutations on predictability and efficacy of treatment with Na(+) channel-blocking drugs.
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Affiliation(s)
- Zheng I Zhu
- Department of Physiology and Biophysics, Institute for Computational Biomedicine, Weill Medical College of Cornell University, New York, NY 10021, USA
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Sumiyoshi M, Hayashi H, Ichinose T, Itoh S, Kawamura M, Suwa S, Sakurai H. Two Cases of Pilsicainide Intoxication showing the Brugada-type Electrocardiographic Findings and Incessant Wide QRS Tachycardia. J Arrhythm 2008. [DOI: 10.1016/s1880-4276(08)80032-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Joshi S, Raiszadeh F, Pierce W, Steinberg JS. Antiarrhythmic induced electrical storm in Brugada syndrome: a case report. Ann Noninvasive Electrocardiol 2007; 12:274-8. [PMID: 17617073 PMCID: PMC6932674 DOI: 10.1111/j.1542-474x.2007.00171.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Brugada syndrome (BS) may be "unmasked" by several pharmacological and/or physiological agents in an otherwise normal electrocardiogram. Once diagnosed the possibility of persistent ventricular tachycardia/fibrillation exists. Although this is treated with various antiarrhythmic agents, there remains a cohort of patients who fail to respond to conventional antiarrhythmic therapy therefore, amplifying the electrical storm. We report a case of a BS diagnosed via procainamide challenge, the resultant near fatal electrical storm aggravated by amiodarone and the eventual resolution with isoproterenol.
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Affiliation(s)
- Sandeep Joshi
- Division of Cardiology, St. Luke's-Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York, NY 10025, USA.
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Chinushi M, Komura S, Izumi D, Furushima H, Tanabe Y, Washizuka T, Aizawa Y. Incidence and Initial Characteristics of Pilsicainide-Induced Ventricular Arrhythmias in Patients With Brugada Syndrome. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2007; 30:662-71. [PMID: 17461877 DOI: 10.1111/j.1540-8159.2007.00728.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND In patients with Brugada syndrome, class I antiarrhythmic drugs can trigger ventricular arrhythmias (VA). The incidence and initial characteristics of VA that developed after pilsicainide was examined in 28 patients with Brugada-type electrocardiographic (ECG) abnormalities and with a positive response in the pilsicainide test. The clinical outcome was also compared between patients with and without pilsicainide-induced VA. METHODS AND RESULTS In all patients, pilsicainide increased ST segment elevation and accentuated type 1 ECG changes. Ventricular tachycardia (VT) developed in 3 patients and premature ventricular complexes (PVC) in 2 other patients. These 5 patients (group I) had higher ST segment elevation in lead V2 on the ECG at baseline and after pilsicainide and showed a longer QTc interval after pilsicainide than the other 23 patients (group II). However, there was no difference between the 2 groups regarding incidence of prior cardiac events, results of signal-averaged ECG, HV interval, inducibility of ventricular fibrillation by programmed electrical stimulation, or QRS duration. In 1 patient, PVC originated from 3 sites, 2 of which triggered polymorphic VT. The right ventricular (RV) outflow tract was the origin of 2 types of PVC, and other RV sites of 5 other types. During a 45 +/- 37 months follow-up, polymorphic VT recurred in 2 patients in group II. CONCLUSIONS Pilsicainide induced VA in some patients with Brugada syndrome, but this result may not be used as a parameter of the risk stratification of Brugada syndrome. Multiple PVC induced by pilsicainide and triggering polymorphic VT originated from several RV sites is an important factor when considering patients for treatment with catheter ablation.
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Affiliation(s)
- Masaomi Chinushi
- School of Health Science, Niigata University School of Medicine, Asahimachi Niigata, Japan.
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Abstract
First introduced as a new clinical entity in 1992, the Brugada syndrome is associated with a relatively high risk of sudden death in young adults, and occasionally in children and infants. Recent years have witnessed a striking proliferation of papers dealing with the clinical and basic aspects of the disease. Characterized by a coved-type ST-segment elevation in the right precordial leads of the electrocardiogram (ECG), the Brugada syndrome has a genetic basis that thus far has been linked only to mutations in SCN5A, the gene that encodes the alpha-subunit of the sodium channel. The Brugada ECG is often concealed, but can be unmasked or modulated by a number of drugs and pathophysiological states including sodium channel blockers, a febrile state, vagotonic agents, tricyclic antidepressants, as well as cocaine and propranolol intoxication. Average age at the time of initial diagnosis or sudden death is 40 +/- 22, with the youngest patient diagnosed at 2 days of age and the oldest at 84 years. This review provides an overview of the clinical, genetic, molecular, and cellular aspects of the Brugada syndrome, incorporating the results of two recent consensus conferences. Controversies with regard to risk stratification and newly proposed pharmacologic strategies are discussed.
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Stokoe KS, Balasubramaniam R, Goddard CA, Colledge WH, Grace AA, Huang CLH. Effects of flecainide and quinidine on arrhythmogenic properties of Scn5a+/- murine hearts modelling the Brugada syndrome. J Physiol 2007; 581:255-75. [PMID: 17303635 PMCID: PMC2075209 DOI: 10.1113/jphysiol.2007.128785] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Brugada syndrome (BrS) is associated with a loss of Na+ channel function and an increased incidence of rapid polymorphic ventricular tachycardia (VT) and sudden cardiac death. A programmed electrical stimulation (PES) technique assessed arrhythmic tendency in Langendorff-perfused wild-type (WT) and genetically modified (Scn5a+/-) 'loss-of-function' murine hearts in the presence and absence of flecainide and quinidine, and the extent to which Scn5a+/- hearts model the human BrS. Extra-stimuli (S2), applied to the right ventricular epicardium, followed trains of pacing stimuli (S1) at progressively reduced S1-S2 intervals. These triggered VT in 16 out of 29 untreated Scn5a+/- and zero out of 31 WT hearts. VT occurred in 11 out of 16 (10 microM) flecainide-treated WT and nine out of the 13 initially non-arrhythmogenic Scn5a+/- hearts treated with (1.0 microM) flecainide. Quinidine (10 microM) prevented VT in six out of six flecainide-treated WT and 13 out of the 16 arrhythmogenic Scn5a+/- hearts in parallel with its clinical effects. Paced electrogram fractionation analysis demonstrated increased electrogram durations, expressed as electrogram duration (EGD) ratios, with shortening S1-S2 intervals in arrhythmogenic Scn5a+/- hearts, and prolonged ventricular effective refractory periods (VERPs) in non-arrhythmogenic Scn5a+/- hearts. Flecainide increased EGD ratios in WT (at 10 microM) and non-arrhythmogenic Scn5a+/- hearts (at 1.0 microM), whereas quinidine (10 microM) reduced EGD ratios and prolonged VERPs in WT and arrhythmogenic Scn5a+/- hearts. However, epicardial and endocardial monophasic action potential recordings consistently demonstrated positive gradients of repolarization in WT, arrhythmogenic and non-arrhythmogenic Scn5a+/- hearts under all pharmacological conditions. Together, these findings demonstrate proarrhythmic effects of flecainide in WT and Scn5a+/- murine hearts that recapitulate its clinical effects. They further attribute the arrhythmogenic phenomena observed here to re-entrant substrates resulting from delayed epicardial activation despite an absence of transmural heterogeneities of repolarization, in sharp contrast to recent characterizations in 'gain-of-function' Scn5a+/Delta murine hearts modelling the long-QT(3) syndrome.
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Affiliation(s)
- Kate S Stokoe
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
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Clancy CE, Zhu ZI, Rudy Y. Pharmacogenetics and anti-arrhythmic drug therapy: a theoretical investigation. Am J Physiol Heart Circ Physiol 2007; 292:H66-75. [PMID: 16997895 PMCID: PMC2034498 DOI: 10.1152/ajpheart.00312.2006] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Pharmacological management of cardiac arrhythmias has been a long and widely sought goal. One of the difficulties in treating arrhythmia stems, in part, from incomplete understanding of the mechanisms of drug block and how intrinsic properties of channel gating affect drug access, binding affinity, and unblock. In the last decade, a plethora of genetic information has revealed that genetics may play a critical role in determining arrhythmia susceptibility and in efficacy of pharmacological therapy. In this context, we present a theoretical approach for investigating effects of drug-channel interaction. We use as an example open-channel or inactivated-channel block by the local anesthetics mexiletine and lidocaine, respectively, of normal and DeltaKPQ mutant Na(+) channels associated with the long-QT syndrome type 3. Results show how kinetic properties of channel gating, which are affected by mutations, are important determinants of drug efficacy. Investigations of Na(+) channel blockade are conducted at multiple scales (single channel and macroscopic current) and, importantly, during the cardiac action potential (AP). Our findings suggest that channel mean open time is a primary determinant of open state blocker efficacy. Channels that remain in the open state longer, such as the DeltaKPQ mutant channels in the abnormal burst mode, are blocked preferentially by low mexiletine concentrations. AP simulations confirm that a low dose of mexiletine can remove early afterdepolarizations and restore normal repolarization without affecting the AP upstroke. The simulations also suggest that inactivation state block by lidocaine is less effective in restoring normal repolarization and adversely suppresses peak Na(+) current.
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Affiliation(s)
- Colleen E Clancy
- Dept. of Physiology and Biophysics, Insitute for Computational Biomedicine, Weill Medical College of Cornell Univeristy, 1300 York Ave., LC-501E, New York, NY 10021, USA.
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Abstract
The 12-lead ECG has limited utility to predict the risk for sudden cardiac death in common cardiac diseases such as coronary artery disease and idiopathic dilated cardiomyopathy. However, it is quite useful in diagnosing less common cardiac conditions that are associated with an increased risk for sudden death.
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Affiliation(s)
- Peter Ott
- Sarver Heart Center, University of Arizona Health Sciences Center, 1501 N. Campbell Avenue, Tucson, AZ 85724, USA.
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