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Karadeniz C. Importance of electrocardiographic markers in predicting cardiac events in children. Biomark Med 2020; 14:1679-1689. [PMID: 33336595 DOI: 10.2217/bmm-2020-0391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
ECG is a common diagnostic tool in medical practice. Sudden cardiac death (SCD) is a rare but devastating event. The most common cause of SCD in the young is a primary arrhythmic event, which is often produced by malignant ventricular arrhythmia. Several electrocardiographic markers for ventricular repolarization and depolarization have been proposed to predict this arrhythmic risk and SCD in children. Although many of these parameters can easily be used in clinical practice, some of them need specific techniques for interpretation. In this review, we summarized the current knowledge regarding the clinical importance and the ability of these ECG parameters to predict adverse cardiac events in the pediatric population.
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Affiliation(s)
- Cem Karadeniz
- Department of Pediatric Cardiology, Pediatric Arrhythmia & Electrophysiology, School of Medicine, Kâtip Celebi University, Izmir, Turkey
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2
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Coronel R. The Future of Physiology: Cardiac Electrophysiology. Front Physiol 2020; 11:854. [PMID: 32760295 PMCID: PMC7373798 DOI: 10.3389/fphys.2020.00854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/25/2020] [Indexed: 11/18/2022] Open
Abstract
Is cardiac electrophysiology complete? What are the challenges that are to be met in cardiac electrophysiology and how can we best engage these? These questions will be addressed in view of the progressing subspecialization of the field. A suggested answer lies in multidisciplinary and extradisciplinary approaches.
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Affiliation(s)
- R Coronel
- Department of Experimental Cardiology, Academic Medical Center, Amsterdam, Netherlands
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3
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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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4
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Boukens BJ, Meijborg VMF, Belterman CN, Opthof T, Janse MJ, Schuessler RB, Coronel R, Efimov IR. Local transmural action potential gradients are absent in the isolated, intact dog heart but present in the corresponding coronary-perfused wedge. Physiol Rep 2018; 5:e13251. [PMID: 28554962 PMCID: PMC5449556 DOI: 10.14814/phy2.13251] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 03/20/2017] [Accepted: 03/20/2017] [Indexed: 11/24/2022] Open
Abstract
The left ventricular (LV) coronary‐perfused canine wedge preparation is a model commonly used for studying cardiac repolarization. In wedge studies, transmembrane potentials typically are recorded; whereas, extracellular electrical recordings are commonly used in intact hearts. We compared electrically measured activation recovery interval (ARI) patterns in the intact heart with those recorded at the same location in the LV wedge preparation. We also compared electrically recorded and optically obtained ARIs in the LV wedge preparation. Five Langendorff‐perfused canine hearts were paced from the right atrium. Local activation and repolarization times were measured with eight transmural needle electrodes. Subsequently, left ventricular coronary‐perfused wedge preparations were prepared from these hearts while the electrodes remained in place. Three electrodes remained at identical positions as in the intact heart. Both electrograms and optical action potentials were recorded (pacing cycle length 400–4000 msec) and activation and repolarization patterns were analyzed. ARIs found in the subepicardium were shorter than in the subendocardium in the LV wedge preparation but not in the intact heart. The transmural ARI gradient recorded at the cut surface of the wedge was not different from that recorded internally. ARIs recorded internally and at the cut surface in the LV wedge preparation, both correlated with optically recorded action potentials. ARI and RT gradients in the LV wedge preparation differed from those in the intact canine heart, implying that those observations in human LV wedge preparations also should be extrapolated to the intact human heart with caution.
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Affiliation(s)
- Bastiaan J Boukens
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia.,Department of Medical Biology, University of Amsterdam, Amsterdam, The Netherlands
| | - Veronique M F Meijborg
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands.,Netherlands Heart Institute, Holland Heart House, Utrecht, The Netherlands
| | - Charly N Belterman
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands.,Institut LIRYC, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac- Bordeaux, France
| | - Tobias Opthof
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands.,Department of Medical Physiology, University of Utrecht, Utrecht, The Netherlands
| | - Michiel J Janse
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Ruben Coronel
- Department of Experimental and Clinical Cardiology, University of Amsterdam, Amsterdam, The Netherlands.,Institut LIRYC, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac- Bordeaux, France
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia.,Institut LIRYC, Electrophysiology and Heart Modeling Institute, fondation Bordeaux Université, Pessac- Bordeaux, France
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Tse G, Yan BP. Traditional and novel electrocardiographic conduction and repolarization markers of sudden cardiac death. Europace 2018; 19:712-721. [PMID: 27702850 DOI: 10.1093/europace/euw280] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/11/2016] [Indexed: 12/20/2022] Open
Abstract
Sudden cardiac death, frequently due to ventricular arrhythmias, is a significant problem globally. Most affected individuals do not arrive at hospital in time for medical treatment. Therefore, there is an urgent need to identify the most-at-risk patients for insertion of prophylactic implantable cardioverter defibrillators. Clinical risk markers derived from electrocardiography are important for this purpose. They can be based on repolarization, including corrected QT (QTc) interval, QT dispersion (QTD), interval from the peak to the end of the T-wave (Tpeak - Tend), (Tpeak - Tend)/QT, T-wave alternans (TWA), and microvolt TWA. Abnormal repolarization properties can increase the risk of triggered activity and re-entrant arrhythmias. Other risk markers are based solely on conduction, such as QRS duration (QRSd), which is a surrogate marker of conduction velocity (CV) and QRS dispersion (QRSD) reflecting CV dispersion. Conduction abnormalities in the form of reduced CV, unidirectional block, together with a functional or a structural obstacle, are conditions required for circus-type or spiral wave re-entry. Conduction and repolarization can be represented by a single parameter, excitation wavelength (λ = CV × effective refractory period). λ is an important determinant of arrhythmogenesis in different settings. Novel conduction-repolarization markers incorporating λ include Lu et al.' index of cardiac electrophysiological balance (iCEB: QT/QRSd), [QRSD× (Tpeak - Tend)/QRSd] and [QRSD × (Tpeak - Tend)/(QRSd × QT)] recently proposed by Tse and Yan. The aim of this review is to provide up to date information on traditional and novel markers and discuss their utility and downfalls for risk stratification.
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Affiliation(s)
- Gary Tse
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, SAR, P.R. China
| | - Bryan P Yan
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, SAR, P.R. China.,Department of Epidemiology and Preventive Medicine, Monash University, Clayton, VIC, Australia
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Meta-analysis of T peak-T end and T peak-T end/QT ratio for risk stratification in congenital long QT syndrome. J Electrocardiol 2018; 51:396-401. [PMID: 29550106 DOI: 10.1016/j.jelectrocard.2018.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Revised: 02/13/2018] [Accepted: 03/06/2018] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND OBJECTIVES Congenital long QT syndrome (LQTS) predisposes affected individuals to ventricular tachycardia/fibrillation (VF/VF), potentially resulting in sudden cardiac death. The Tpeak-Tend interval and the Tpeak-Tend/QT ratio, electrocardiographic markers of dispersion of ventricular repolarization, were proposed for risk stratification but their predictive values in LQTS have been controversial. A systematic review and meta-analysis was conducted to examine the value of Tpeak-Tend intervals and Tpeak-Tend/QT ratios in predicting arrhythmic and mortality outcomes in congenital LQTS. METHOD PubMed and Embase databases were searched until 9th May 2017, identifying 199 studies. RESULTS Five studies on long QT syndrome were included in the final meta-analysis. Tpeak-Tend intervals were longer (mean difference [MD]: 13ms, standard error [SE]: 4ms, P=0.002; I2=34%) in congenital LQTS patients with adverse events [syncope, ventricular arrhythmias or sudden cardiac death] compared to LQTS patients without such events. By contrast, Tpeak-Tend/QT ratios were not significantly different between the two groups (MD: 0.02, SE: 0.02, P=0.26; I2=0%). CONCLUSION This meta-analysis showed that Tpeak-Tend interval is significant higher in individuals who are at elevated risk of adverse events in congenital LQTS, offering incremental value for risk stratification.
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Nademanee K, Wilde AA. Repolarization Versus Depolarization Defects in Brugada Syndrome. JACC Clin Electrophysiol 2017; 3:364-366. [DOI: 10.1016/j.jacep.2017.01.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 01/19/2017] [Indexed: 10/19/2022]
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8
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Boukens BJ, Sulkin MS, Gloschat CR, Ng FS, Vigmond EJ, Efimov IR. Transmural APD gradient synchronizes repolarization in the human left ventricular wall. Cardiovasc Res 2015. [PMID: 26209251 DOI: 10.1093/cvr/cvv202] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS The duration and morphology of the T wave predict risk for ventricular fibrillation. A transmural gradient in action potential duration (APD) in the ventricular wall has been suggested to underlie the T wave in humans. We hypothesize that the transmural gradient in APD compensates for the normal endocardium-to-epicardium activation sequence and synchronizes repolarization in the human ventricular wall. METHODS AND RESULTS We made left ventricular wedge preparations from 10 human donor hearts and measured transmural activation and repolarization patterns by optical mapping, while simultaneously recording a pseudo-ECG. We also studied the relation between local timings of repolarization with the T wave in silico. During endocardial pacing (1 Hz), APD was longer at the subendocardium than at the subepicardium (360 ± 17 vs. 317 ± 20 ms, P < 0.05). The transmural activation time was 32 ± 4 ms and resulted in final repolarization of the subepicardium at 349 ± 18 ms. The overall transmural dispersion in repolarization time was smaller than that of APD. During epicardial pacing, the dispersion in repolarization time increased, whereas that of APD remained similar. The morphology of the T wave did not differ between endocardial and epicardial stimulation. Simulations explained the constant T wave morphology without transmural APD gradients. CONCLUSION The intrinsic transmural difference in APD compensates for the normal cardiac activation sequence, resulting in more homogeneous repolarization of the left ventricular wall. Our data suggest that the transmural repolarization differences do not fully explain the genesis of the T wave.
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Affiliation(s)
- Bastiaan J Boukens
- Department of Biomedical Engineering, George Washington University, 5000 Science and Engineering Hall, 800 22ng Street NW, Washington, DC 20052, USA
| | - Matthew S Sulkin
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | - Chris R Gloschat
- Department of Biomedical Engineering, George Washington University, 5000 Science and Engineering Hall, 800 22ng Street NW, Washington, DC 20052, USA
| | - Fu Siong Ng
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Edward J Vigmond
- Institut LIRYC, and Institut de Mathématiques de Bordeaux, Université de Bordeaux, Bordeaux, France
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, 5000 Science and Engineering Hall, 800 22ng Street NW, Washington, DC 20052, USA Department of Biomedical Engineering, Washington University, St. Louis, MO, USA Institut LIRYC, and Institut de Mathématiques de Bordeaux, Université de Bordeaux, Bordeaux, France
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9
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Analysis of Unipolar Electrograms in Rabbit Heart Demonstrated the Key Role of Ventricular Apicobasal Dispersion in Arrhythmogenicity. Cardiovasc Toxicol 2014; 14:316-28. [DOI: 10.1007/s12012-014-9254-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Janse MJ, Coronel R, Opthof T, Sosunov EA, Anyukhovsky EP, Rosen MR. Repolarization gradients in the intact heart: transmural or apico-basal? PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 109:6-15. [PMID: 22446189 DOI: 10.1016/j.pbiomolbio.2012.03.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 02/17/2012] [Accepted: 03/06/2012] [Indexed: 01/31/2023]
Abstract
Controversies regarding the genesis of the T wave in the electrocardiogram and the role of midmural M cells in the intact heart include: In normal, intact canine and human hearts there is no significant transmural gradient in repolarization times. The T wave results primarily from apico-basal differences in repolarization times. Also, in the intact heart there is no midmural region of prolonged action potential duration. This contrasts with isolated preparations, such as the wedge preparation or myocardial slices or disaggregated myocytes in which M cells, with action potentials longer than those of endocardial and epicardial myocardium, can be found. This disparity in action potential duration probably results from partial uncoupling of myocardial cells in the regions where measurements are made, e.g., the cut surface of a wedge preparation. In regions of a wedge where cellular coupling is normal, or in isolated myocardial bundles or sheets, no evidence for M cells is detected. In some wedge preparations, a drug-induced large transmural repolarization gradient, involving M cells, can lead to Torsade de Pointes, possibly caused by so-called phase two reentry. In contrast, when a gradient of repolarization times of more than 100 ms was created in intact hearts, no evidence for reentry was found and no spontaneous arrhythmias occurred. In conclusion, in the intact heart, M cells appear not to contribute to repolarization gradients and arrhythmias. Furthermore, no significant repolarization gradients between endocardium and epicardium exist. The T wave in the body surface electrocardiogram is caused by apico-basal and anterior-posterior differences in repolarization times.
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Affiliation(s)
- Michiel J Janse
- The Experimental Cardiology Group, Heart Centre, Academic Medical Centre, Amsterdam, The Netherlands
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11
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Morin DP, Saad MN, Shams OF, Owen JS, Xue JQ, Abi-Samra FM, Khatib S, Nelson-Twakor OS, Milani RV. Relationships between the T-peak to T-end interval, ventricular tachyarrhythmia, and death in left ventricular systolic dysfunction. Europace 2012; 14:1172-9. [PMID: 22277646 DOI: 10.1093/europace/eur426] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
AIMS The interval between the T-wave's peak and end (Tpe), an electrocardiographic (ECG) index of ventricular repolarization, has been proposed as an indicator of arrhythmic risk. We aimed to clarify the clinical usefulness of Tpe for risk stratification. METHODS AND RESULTS We evaluated 327 patients with left ventricular ejection fraction (LVEF) ≤ 35% (75% male, LVEF 23 ± 7%). All patients had an implanted implantable cardioverter-defibrillator (ICD). Clinical data and ECGs were analysed at baseline. Prospective follow-up for the endpoints of appropriate ICD therapy and mortality was conducted via periodic device interrogation, chart review, and the Social Security Death Index. During device clinic follow-up of 17 ± 12 months, 59 (18%) patients had appropriate ICD therapy, and during mortality follow-up of 30 ± 13 months, 67 (21%) patients died. A longer Tpe(c) predicted appropriate ICD therapy, death, and the combination of appropriate ICD therapy or death (P< 0.01 for each endpoint). On multivariable analysis correcting for other univariable predictors, Tpe(c) remained predictive of ICD therapy [hazard ratio (HR) per 10 ms increase: 1.16, P= 0.02], all-cause mortality (HR per 10 ms: 1.14, P= 0.03), and the composite endpoint of ICD therapy or death (HR per 10 ms: 1.16, P< 0.01). CONCLUSIONS In patients with left ventricular systolic dysfunction and an implanted ICD, Tpe(c) independently predicts both ventricular tachyarrhythmia and overall mortality.
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Affiliation(s)
- Daniel P Morin
- Ochsner Medical Center, 1514 Jefferson Highway, New Orleans, LA 70121, USA.
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12
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Letter by Opthof et al Regarding Article, “Prolonged Tpeak to Tend Interval on the Resting Electrocardiogram Is Associated With Increased Risk of Sudden Cardiac Death”. Circ Arrhythm Electrophysiol 2011; 4:e87; author reply e88. [DOI: 10.1161/circep.111.965566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Janse MJ, Coronel R, Opthof T. Rebuttal to M cells are present in the ventricular myocardium. Heart Rhythm 2011; 8:1100. [DOI: 10.1016/j.hrthm.2011.04.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Indexed: 10/18/2022]
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Wilde AAM, Postema PG, Di Diego JM, Viskin S, Morita H, Fish JM, Antzelevitch C. The pathophysiological mechanism underlying Brugada syndrome: depolarization versus repolarization. J Mol Cell Cardiol 2010; 49:543-53. [PMID: 20659475 DOI: 10.1016/j.yjmcc.2010.07.012] [Citation(s) in RCA: 253] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 07/13/2010] [Accepted: 07/19/2010] [Indexed: 12/29/2022]
Abstract
This Point/Counterpoint presents a scholarly debate of the mechanisms underlying the electrocardiographic and arrhythmic manifestations of Brugada syndrome (BrS), exploring in detail the available evidence in support of the repolarization vs. depolarization hypothesis.
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Affiliation(s)
- Arthur A M Wilde
- Department of Cardiology, Academic Medical Center Amsterdam, Amsterdam, The Netherlands
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15
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Patel C, Burke JF, Patel H, Gupta P, Kowey PR, Antzelevitch C, Yan GX. Is there a significant transmural gradient in repolarization time in the intact heart? Cellular basis of the T wave: a century of controversy. Circ Arrhythm Electrophysiol 2009; 2:80-8. [PMID: 19808446 DOI: 10.1161/circep.108.791830] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Chinmay Patel
- Main Line Health Heart Center, Lankenau Hospital and Lankenau Institute for Medical Research, Wynnewood, Pa; Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pa; Masonic Medical Research Laboratory, Utica, NY; and Tong-Ji Hospital, Tong-Ji Medical College, Huazhong University of Science and Technology, Wuhan, China
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16
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Opthof T, Coronel R, Janse MJ. Is there a significant transmural gradient in repolarization time in the intact heart?: Repolarization Gradients in the Intact Heart. Circ Arrhythm Electrophysiol 2009; 2:89-96. [PMID: 19808447 DOI: 10.1161/circep.108.825356] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Tobias Opthof
- Experimental Cardiology Group, Center for Heart Failure Research, Academic Medical Center, Amsterdam, The Netherlands
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17
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Voss F, Opthof T, Marker J, Bauer A, Katus HA, Becker R. There is no transmural heterogeneity in an index of action potential duration in the canine left ventricle. Heart Rhythm 2009; 6:1028-34. [PMID: 19560091 DOI: 10.1016/j.hrthm.2009.03.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 03/14/2009] [Indexed: 12/14/2022]
Abstract
BACKGROUND Transmural heterogeneity in ventricular repolarization demonstrated in vitro has been difficult to confirm in vivo. Whether this discrepancy reflects a physiological phenomenon or a methodological problem remains a vivid matter of debate despite a plethora of experimental work. Therefore, we have measured the relevant electrophysiological parameters first in vivo and repeated these in the same heart and at identical sites in vitro. Methodological issues were tackled by using both unipolar and bipolar recordings. Physiological issues were explored by measuring both local and functional electrophysiological parameters. METHODS In 10 healthy dogs, 2 high-resolution needle electrodes were inserted into the left ventricle. Effective refractory periods (ERP) as well as activation recovery intervals (ARI) were determined at each electrode along both needles at basic cycle lengths (BCL) of 850 and 300 ms, respectively. After excision of the heart, ERP and ARI measurements were repeated in the arterially perfused wedge preparations. RESULTS First, we observed that ERPs and ARIs were significantly shorter in vivo than in vitro. Mean ERPs and ARIs of all muscle layers were relatively uniform throughout the ventricular wall in vivo. The transition from the in vivo to the in vitro preparation was associated with a significant albeit small increase of mean ARIs in the subendocardium, whereas interlayer differences in mean ERPs did not reach statistical significance as in vivo. CONCLUSION In the intact canine left ventricular wall, a more or less homogeneous distribution in transmural ERP and ARI is present.
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Affiliation(s)
- Frederik Voss
- University of Heidelberg, Department of Cardiology, Heidelberg, Germany.
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18
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Identifying genetic risk factors for serious adverse drug reactions: current progress and challenges. Nat Rev Drug Discov 2007; 6:904-16. [PMID: 17971785 DOI: 10.1038/nrd2423] [Citation(s) in RCA: 251] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Serious adverse drug reactions (SADRs) are a major cause of morbidity and mortality worldwide. Some SADRs may be predictable, based upon a drug's pharmacodynamic and pharmacokinetic properties. Many, however, appear to be idiosyncratic. Genetic factors may underlie susceptibility to SADRs and the identification of predisposing genotypes may improve patient management through the prospective selection of appropriate candidates. Here we discuss three specific SADRs with an emphasis on genetic risk factors. These SADRs, selected based on wide-sweeping clinical interest, are drug-induced liver injury, statin-induced myotoxicity and drug-induced long QT and torsades de pointes. Key challenges for the discovery of predictive risk alleles for these SADRs are also considered.
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