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Li KHC, Lee S, Yin C, Liu T, Ngarmukos T, Conte G, Yan GX, Sy RW, Letsas KP, Tse G. Brugada syndrome: A comprehensive review of pathophysiological mechanisms and risk stratification strategies. IJC HEART & VASCULATURE 2020; 26:100468. [PMID: 31993492 PMCID: PMC6974766 DOI: 10.1016/j.ijcha.2020.100468] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 01/01/2020] [Accepted: 01/02/2020] [Indexed: 12/17/2022]
Abstract
Brugada syndrome (BrS) is an inherited ion channel channelopathy predisposing to ventricular arrhythmias and sudden cardiac death. Originally believed to be predominantly associated with mutations in SCN5A encoding for the cardiac sodium channel, mutations of 18 genes other than SCN5A have been implicated in the pathogenesis of BrS to date. Diagnosis is based on the presence of a spontaneous or drug-induced coved-type ST segment elevation. The predominant electrophysiological mechanism underlying BrS remains disputed, commonly revolving around the three main hypotheses based on abnormal repolarization, depolarization or current-load match. Evidence from computational modelling, pre-clinical and clinical studies illustrates that molecular abnormalities found in BrS lead to alterations in excitation wavelength (λ), which ultimately elevates arrhythmic risk. A major challenge for clinicians in managing this condition is the difficulty in predicting the subset of patients who will suffer from life-threatening ventricular arrhythmic events. Several repolarization risk markers have been used thus far, but these neglect the contributions of conduction abnormalities in the form of slowing and dispersion. Indices incorporating both repolarization and conduction based on the concept of λ have recently been proposed. These may have better predictive values than the existing markers. Current treatment options include pharmacological therapy to reduce the occurrence of arrhythmic events or to abort these episodes, and interventions such as implantable cardioverter-defibrillator insertion or radiofrequency ablation of abnormal arrhythmic substrate.
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Affiliation(s)
- Ka Hou Christien Li
- Faculty of Medicine, Newcastle University, Newcastle, United Kingdom.,Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, SAR, PR China
| | - Sharen Lee
- Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, SAR, PR China
| | - Chengye Yin
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China
| | - Tachapong Ngarmukos
- Department of Medicine Faculty of Medicine Ramathibodi Hospital Mahidol University, Bangkok, Thailand
| | - Giulio Conte
- Division of Cardiology, Cardiocentro Ticino, Lugano, Switzerland
| | - Gan-Xin Yan
- Lankenau Institute for Medical Research and Lankenau Medical Center, Wynnewood, PA, USA
| | - Raymond W Sy
- Department of Cardiology, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.,Sydney Medical School, University of Sydney, Camperdown, New South Wales, Australia
| | - Konstantinos P Letsas
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Gary Tse
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China.,Xiamen Cardiovascular Hospital, Xiamen University, Xiamen, China
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Tse G, Lee S, Gong M, Mililis P, Asvestas D, Bazoukis G, Roever L, Jeevaratnam K, Hothi SS, Li KHC, Liu T, Letsas KP. Restitution metrics in Brugada syndrome: a systematic review and meta-analysis. J Interv Card Electrophysiol 2019; 57:319-327. [PMID: 31836966 DOI: 10.1007/s10840-019-00675-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/19/2019] [Indexed: 12/15/2022]
Abstract
BACKGROUND Brugada syndrome (BrS) is an ion channelopathy that predisposes affected subjects to ventricular tachycardia/fibrillation (VT/VF) and sudden cardiac death. Restitution analysis has been examined in BrS patients but not all studies have reported significant differences between BrS patients and controls. Therefore, we conducted a systematic review and meta-analysis to investigate the different restitution indices used in BrS. METHODS PubMed and Embase were searched until April 7, 2019, identifying 20 and 27 studies. RESULTS A total of ten studies involving 178 BrS (mean age 38 years old, 63% male) and 102 controls (mean age 31 years old, 42% male) were included in this systematic review. Pacing was carried out at the right ventricular outflow tract (RVOT)/right ventricular apex (RPA) (n = 4), RPA (n = 4), or right atrium (RA) (n = 1). Basic cycle lengths of 400 (n = 4), 500 (n = 2), 600 (n = 6) and 750 ms (n = 1) were used. Recording methods include electrograms (n = 4), monophasic action potentials (n = 5), and electrocardiograms (n = 1). Signals were obtained from the RVOT (n = 8), RVA (n = 3), RA (n = 1), or the body surface (n = 1). The maximum restitution slope for endocardial repolarization at the RVOT was 0.87 for BrS patients (n = 5; 95% confidence interval [CI] 0.68-1.07) compared with 0.74 in control subjects (n = 4; 95% CI 0.42-1.06), with a significant mean difference of 0.40 (n = 4; 95% CI 0.11-0.69; P = 0.007). CONCLUSIONS Steeper endocardial repolarization restitution slopes are found in BrS patients compared with controls at baseline. Restitution analysis can provide important information for risk stratification in BrS.
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Affiliation(s)
- Gary Tse
- Xiamen Cardiovascular Hospital Affiliated to Xiamen University, Xiamen, Fujian, People's Republic of China. .,Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China.
| | - Sharen Lee
- Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, SAR, People's Republic of China
| | - Mengqi Gong
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China
| | - Panagiotis Mililis
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Dimitrios Asvestas
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - George Bazoukis
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Leonardo Roever
- Department of Clinical Research, Federal University of Uberlândia, Uberlândia, MG, Brazil
| | | | - Sandeep S Hothi
- Heart and Lung Centre, New Cross Hospital, Wolverhampton, UK
| | - Ka Hou Christien Li
- Xiamen Cardiovascular Hospital Affiliated to Xiamen University, Xiamen, Fujian, People's Republic of China.,Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China.,Faculty of Medicine, Newcastle University, Newcastle, UK
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, 300211, People's Republic of China
| | - Konstantinos P Letsas
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece.
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