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Salama A, Ibrahim G, Fikry M, Elsannan MH, Eltahlawi M. Prognostic value of high-sensitive troponin T in patients with severe aortic stenosis undergoing valve replacement surgery. Indian J Thorac Cardiovasc Surg 2024; 40:142-150. [PMID: 38389769 PMCID: PMC10879475 DOI: 10.1007/s12055-023-01594-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 02/24/2024] Open
Abstract
Background Aortic stenosis (AS) is a well-known cause of mortality. We aimed to assess the prognostic value of high-sensitive troponin T (hs-TnT) in symptomatic patients with severe AS and preserved left ventricular ejection fraction (LVEF) after surgical aortic valve replacement (AVR). Patients and methods The study recruited patients with severe symptomatic AS fulfilling the inclusion criteria in the period between April 2020 and February 2022. Comprehensive echocardiography was done. The following parameters were assessed: AS severity, LV mass index (LVMI), left atrium volume index (LAVI), and LVEF. E/e' and LVEF were calculated using the biplane method of Simpsons. Global longitudinal strain (GLS) was assessed by speckle tracking echocardiography. Peripheral blood samples were collected for hs-TnT measurement. All patients underwent surgical AVR. The patients were followed for the following 6 months for major adverse cardiovascular events (MACE). MACE was defined as cardiac death, re-admission for congestive heart failure (CHF) and fatal arrhythmia. Results One hundred and eight patients (mean age = 58.7 ± 7.68 years) with severe AS were recruited. Seventeen patients presented with MACE including 8 cardiac deaths. We divided the patients into two groups based on the normal hs-TnT values. The Kaplan-Meier curve revealed a statistically significant difference in MACE rate among troponin groups (log-rank test = 5.06, p = 0.025). There was significant difference between both groups regarding GLS with smaller GLS in negative hs-TnT group. In multivariate analysis, GLS and hs-TnT were significantly associated with MACE (p = 0.022 and < 0.01 respectively). The cutoff value of hs-TnT of 238.25 had a sensitivity of 70% and a specificity of 81% for predicting future MACE. There was a significant correlation between GLS and troponin (p < 0.001). Conclusions hs-TnT is associated with bad short-term prognosis after AVR. hs-TnT and GLS could be significant predictors for future MACE in patients with severe symptomatic AS and preserved LVEF who underwent AVR. Elevated hs-TnT and impaired GLS could set an indication of early intervention in asymptomatic severe AS.
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Affiliation(s)
- Alaa Salama
- Cardiology Department, Zagazig University, Zagazig, Egypt
| | - Ghada Ibrahim
- Cardiology Department, Zagazig University, Zagazig, Egypt
| | - Mohammad Fikry
- Cardiology Department, Zagazig University, Zagazig, Egypt
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2
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Paja SC, Gondoș V, Deaconu S, Cinteză E, Vătășescu R. Case Report: Remote magnetic navigation and accessory pathways ablation in a single ventricle young adult with complex corrective surgeries. Front Pediatr 2024; 12:1358505. [PMID: 38434729 PMCID: PMC10904613 DOI: 10.3389/fped.2024.1358505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/05/2024] [Indexed: 03/05/2024] Open
Abstract
Supraventricular arrhythmias have become an increasingly significant contributor to the risk of mortality and morbidity in adults with complex congenital heart disease (CHD), especially in light of recent advances in palliative corrective surgeries. Because of their unique characteristics, they demand specific treatment approaches. While pharmaco-logical interventions are an option, they have limited effectiveness and may lead to side effects. Although performing radiofrequency ablation (RFA) can be exceptionally challenging in patients with complex CHD, due to particular vascular access and also modified anatomy, it has paved the way to enhance comprehension of the underlying mechanisms of supraventricular arrhythmias. This, in turn, enables the provision of improved therapies and, ultimately, an enhancement in the quality of life and symptom management for these patients. The purpose of this case report is to highlight the benefits of utilizing advanced technologies such as three-dimensional electro-anatomical mapping systems, remote magnetic navigation, and highly flexible mapping and ablation catheters during RFA in a young adult with complex congenital heart disease. Although he lacked venous connections to the right atrium (RA) due to multiple corrective surgeries we, remarkably, were capable to advance a decapolar deflectable diagnostic catheter inside the Fontan tunnel and from there to record and stimulate the RA. Successful ablation of two accessory pathways was achieved with no arrhythmia recurrence during follow-up.
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Affiliation(s)
| | - Viviana Gondoș
- Department of Medical Electronics and Informatics, Polytechnic University of Bucharest, Bucharest, Romania
| | | | - Eliza Cinteză
- Department of Pediatric Cardiology, “Marie Curie” Emergency Children’s Hospital, Bucharest, Romania
- 4th Department — Cardio-Thoracic Pathology, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
| | - Radu Vătășescu
- Cardiology Department, Clinic Emergency Hospital, Bucharest, Romania
- 4th Department — Cardio-Thoracic Pathology, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
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3
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Zhong Z, Li Q, Zou X, Ouyang Q, Zeng Q, Hu Y, Wang M, Luo Y, Yao D. Influence of Sleep Bruxism on QTc Interval and QT Variability in Patients with OSA: a pilot study. J Oral Rehabil 2022; 49:495-504. [PMID: 35158405 DOI: 10.1111/joor.13314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 01/29/2022] [Accepted: 02/08/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND Obstructive sleep apnea (OSA) is associated with increases in QT interval corrected for heart rate (QTc interval) and QT variability index (QTVI) and sleep bruxism (SB) is prevalent in OSA patients. OBJECTIVES To examine whether QTc interval and QT variability were changed during episodes of RMMAs/SB in SB patients with and without OSA. METHODS The RR and QTc intervals, and QTVI during RMMAs with or without accompanied limb movements (RMMAs/LMs) in 10 normal controls and 10 SB patients without OSA and during apneic and recovery periods of OSA in 10 SB patients with OSA were analyzed. RESULTS In the SB patients without OSA and controls, QTc intervals and QTVI were significantly increased during RMMAs/LMs compared with those during the 10 s periods (from 10th to 20th s) before the onset and after the offset of RMMAs/LMs, and significantly increased during RMMAs/LMs with awakenings compared with those with microarousals and no arousals. Moreover, QTc interval and QTVI were positively correlated with the duration of RMMAs/LMs. Moreover, in the SB patients with OSA, QTc interval and QTVI during the recovery period of OSA events were significantly longer and higher than those during the apneic period regardless of accompanied RMMAs/LMs, and QTc interval and QTVI during the apneic and recovery periods accompanied with RMMAs/LMs were significantly longer and higher than those without accompanied RMMAs/LMs. CONCLUSION OSA and RMMAs/LMs events were associated with longer QTc intervals and higher QTVI, and RMMAs/LMs might contribute to these changes associated with OSA events accompanied with RMMAs/LMs.
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Affiliation(s)
- Zhijun Zhong
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang Medical College and Nanchang University, Jiangxi, PR China
| | - Qi Li
- Department of Neurology, the Third Affiliated Hospital, Nanchang University, Jiangxi, PR China
| | - Xueliang Zou
- Jiangxi Mental Hospital, Nanchang University, Jiangxi, PR China
| | - Qian Ouyang
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang Medical College and Nanchang University, Jiangxi, PR China
| | - Qinghong Zeng
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang Medical College and Nanchang University, Jiangxi, PR China.,School of Pharmaceutical Sciences, Nanchang University, Jiangxi, PR China
| | - Yinyin Hu
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang Medical College and Nanchang University, Jiangxi, PR China.,School of Pharmaceutical Sciences, Nanchang University, Jiangxi, PR China
| | - Mengmeng Wang
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang Medical College and Nanchang University, Jiangxi, PR China.,School of Pharmaceutical Sciences, Nanchang University, Jiangxi, PR China
| | - Yaxing Luo
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang Medical College and Nanchang University, Jiangxi, PR China.,School of Pharmaceutical Sciences, Nanchang University, Jiangxi, PR China
| | - Dongyuan Yao
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, Nanchang Medical College and Nanchang University, Jiangxi, PR China
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4
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Tse G, Li KHC, Cheung CKY, Letsas KP, Bhardwaj A, Sawant AC, Liu T, Yan GX, Zhang H, Jeevaratnam K, Sayed N, Cheng SH, Wong WT. Arrhythmogenic Mechanisms in Hypokalaemia: Insights From Pre-clinical Models. Front Cardiovasc Med 2021; 8:620539. [PMID: 33614751 PMCID: PMC7887296 DOI: 10.3389/fcvm.2021.620539] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/13/2021] [Indexed: 12/21/2022] Open
Abstract
Potassium is the predominant intracellular cation, with its extracellular concentrations maintained between 3. 5 and 5 mM. Among the different potassium disorders, hypokalaemia is a common clinical condition that increases the risk of life-threatening ventricular arrhythmias. This review aims to consolidate pre-clinical findings on the electrophysiological mechanisms underlying hypokalaemia-induced arrhythmogenicity. Both triggers and substrates are required for the induction and maintenance of ventricular arrhythmias. Triggered activity can arise from either early afterdepolarizations (EADs) or delayed afterdepolarizations (DADs). Action potential duration (APD) prolongation can predispose to EADs, whereas intracellular Ca2+ overload can cause both EADs and DADs. Substrates on the other hand can either be static or dynamic. Static substrates include action potential triangulation, non-uniform APD prolongation, abnormal transmural repolarization gradients, reduced conduction velocity (CV), shortened effective refractory period (ERP), reduced excitation wavelength (CV × ERP) and increased critical intervals for re-excitation (APD-ERP). In contrast, dynamic substrates comprise increased amplitude of APD alternans, steeper APD restitution gradients, transient reversal of transmural repolarization gradients and impaired depolarization-repolarization coupling. The following review article will summarize the molecular mechanisms that generate these electrophysiological abnormalities and subsequent arrhythmogenesis.
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Affiliation(s)
- 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, China.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Ka Hou Christien Li
- Faculty of Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - Konstantinos P Letsas
- Second Department of Cardiology, Laboratory of Cardiac Electrophysiology, Evangelismos General Hospital of Athens, Athens, Greece
| | - Aishwarya Bhardwaj
- Division of Cardiology, Department of Internal Medicine, State University of New York at Buffalo, Buffalo, NY, United States
| | - Abhishek C Sawant
- Division of Cardiology, Department of Internal Medicine, State University of New York at Buffalo, Buffalo, NY, United States
| | - 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, China
| | - Gan-Xin Yan
- Lankenau Institute for Medical Research and Lankenau Medical Center, Wynnewood, PA, United States
| | - Henggui Zhang
- School of Physics and Astronomy, The University of Manchester, Manchester, United Kingdom
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Nazish Sayed
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, United States.,Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, United States.,Department of Medicine, Division of Cardiology, Stanford University School of Medicine, Stanford, CA, United States
| | - Shuk Han Cheng
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Science, City University of Hong Kong, Hong Kong, China.,State Key Laboratory of Marine Pollution (SKLMP), City University of Hong Kong, Hong Kong, China.,Department of Materials Science and Engineering, College of Science and Engineering, City University of Hong Kong, Hong Kong, China
| | - Wing Tak Wong
- School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China
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5
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Heger J, Trimaille A, Kibler M, Marchandot B, Peillex M, Carmona A, Matsushita K, Trinh A, Reydel A, Zeyons F, Petit-Eisenmann H, Jesel L, Ohlmann P, Morel O. Electrocardiographic Strain Pattern Is a Major Determinant of Rehospitalization for Heart Failure After Transcatheter Aortic Valve Replacement. J Am Heart Assoc 2021; 10:e014481. [PMID: 33459031 PMCID: PMC7955442 DOI: 10.1161/jaha.119.014481] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Electrocardiographic strain pattern (ESP) has recently been associated with increased adverse outcome in aortic stenosis and after surgical aortic valve replacement. Our study sought to determine the impact and incremental value of ESP pattern in predicting adverse outcome after transcatheter aortic valve replacement. Methods and Results A total of 585 patients with severe aortic stenosis (mean age, 83±7 years; men, 39.8%) were enrolled for transcatheter aortic valve replacement from November 2012 to May 2018. ESP was defined as ≥1-mm concave down-sloping ST-segment depression and asymmetrical T-wave inversion in the lateral leads. The primary end points of the study were all-cause mortality, rehospitalization for heart failure, myocardial infarction, and stroke. A total of 178 (30.4%) patients were excluded because of left bundle-branch block (n=103) or right bundle-branch block (n=75). Among the 407 remaining patients, 106 had ESP (26.04%). At a median follow-up of 20.00 months (11.70-29.42 months), no impact of electric strain on overall and cardiac death could be established. By contrast, incidence of rehospitalization for heart failure was significantly higher (33/106 [31.1%] versus 33/301 [11%]; P<0.001) in patients with ESP. By multivariate analyses, ESP remained a strong predictor of rehospitalization for heart failure (hazard ratio, 2.75 [95% CI, 1.61-4.67]; P<0.001). Conclusions In patients with aortic stenosis who were eligible for transcatheter aortic valve replacement, ESP is frequent and associated with an increased risk of postinterventional heart failure regardless of preoperative left ventricular hypertrophy. ESP represents an easy, objective, reliable, and low-cost tool to identify patients who may benefit from intensified postinterventional follow-up.
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Affiliation(s)
- Joé Heger
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Antonin Trimaille
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Marion Kibler
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Benjamin Marchandot
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Marilou Peillex
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Adrien Carmona
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Kensuke Matsushita
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Annie Trinh
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Antje Reydel
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Floriane Zeyons
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Hélène Petit-Eisenmann
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Laurence Jesel
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France.,Unité mixte de recherche (UMR) Institut national de la santé et de la recherche médicale (INSERM) 1260 Regenerative Nanomedicine Université de Strasbourg France
| | - Patrick Ohlmann
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France
| | - Olivier Morel
- Pôle d'Activité Médico-Chirurgicale Cardio-Vasculaire Nouvel Hôpital CivilCentre Hospitalier UniversitaireUniversité de Strasbourg Strasbourg France.,Unité mixte de recherche (UMR) Institut national de la santé et de la recherche médicale (INSERM) 1260 Regenerative Nanomedicine Université de Strasbourg France
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6
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Arinze NC, Eyituoyo HO, Aben RN, Vu DP, Haithcock DB, Poku J, Sogade FO. Successful Radiofrequency Ablation of Recurrent Supraventricular Tachycardia in a Patient with Complex Congenital Heart Disease. AMERICAN JOURNAL OF CASE REPORTS 2020; 21:e928147. [PMID: 33262322 PMCID: PMC7719496 DOI: 10.12659/ajcr.928147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Radiofrequency ablation (RFA) is the criterion standard treatment for patients with atrioventricular nodal reentrant tachycardia (AVNRT). Knowledge about RFA in patients with dextrocardia and situs inversus is limited due to their rare incidence and complexity. The incidence of dextrocardia is reported to be 1 in 12 000 births, with situs inversus occurring in one-third of the cases. The incidence of congenital heart disease is about 5% in these patients. However, data on rhythm and conduction disorders in this group of patients are currently limited, making management more difficult owing to their individual anatomy. CASE REPORT We report the case of an obese 21-year-old man with complex congenital heart disease (CCHD) (situs inversus dextrocardia, pulmonary atresia, single ventricle, common atrium with single atrioventricular valve), asplenia, and multiple cardiac-corrective surgeries (Fontan repair, bidirectional Glenn anastomosis, and Blalock-Taussig shunt) who underwent successful RFA of recurrent supraventricular tachycardia. CONCLUSIONS Supraventricular arrhythmias are common in the setting of CCHD. Although catheter ablation procedures are technically challenging to perform in patients with CCHD, they remain the best therapeutic option for these arrhythmias. To our knowledge, this case is the first to be described in the literature of successful ablation of AVNRT in a patient with situs inversus dextrocardia, pulmonary atresia, a single ventricle, a common atrium with a single atrioventricular valve, and multiple cardiac-corrective surgeries.
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Affiliation(s)
- Nkechi Christiana Arinze
- Department of Internal Medicine/Community Medicine, Mercer University School of Medicine, Macon, GA, USA
| | - Harry O Eyituoyo
- Department of Internal Medicine/Community Medicine, Mercer University School of Medicine, Macon, GA, USA
| | - Rieta N Aben
- Department of Internal Medicine/Community Medicine, Mercer University School of Medicine, Macon, GA, USA
| | - Dat P Vu
- Department of Internal Medicine/Community Medicine, Mercer University School of Medicine, Macon, GA, USA
| | - Daniel B Haithcock
- Department of Cardiology and Electrophysiology, Georgia Arrhythmia Consultants and Research Institute, Macon, GA, USA.,Department of Cardiology and Electrophysiology, Navicent Health, Macon, GA, USA
| | - Joseph Poku
- Department of Cardiology and Electrophysiology, Georgia Arrhythmia Consultants and Research Institute, Macon, GA, USA.,Department of Cardiology and Electrophysiology, Navicent Health, Macon, GA, USA
| | - Felix O Sogade
- Department of Cardiology and Electrophysiology, Georgia Arrhythmia Consultants and Research Institute, Macon, GA, USA.,Department of Cardiology and Electrophysiology, Navicent Health, Macon, GA, USA
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7
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Ayee MAA, Bunker BC, De Groot JL. Membrane modulatory effects of omega-3 fatty acids: Analysis of molecular level interactions. CURRENT TOPICS IN MEMBRANES 2020; 86:57-81. [PMID: 33837698 DOI: 10.1016/bs.ctm.2020.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bioactive omega-3 polyunsaturated fatty acids have been shown to reduce the risk of death in patients with cardiovascular disease and alleviate the symptoms of other inflammatory diseases. However, the mechanisms of action of these effects remain unclear. It has been postulated that omega-3 polyunsaturated fatty acids modify cell membranes by incorporation into the membrane and altering the signaling properties of cellular receptors. In this chapter, we explore the effects of omega-3 polyunsaturated fatty acids on cell membrane structure and function. We present a review of the current evidence for the health benefits of these compounds and explore the molecular mechanisms through which omega-3 polyunsaturated fatty acids interact with membrane lipids and modulate bilayer structure. Using computational models of multicomponent phospholipid bilayers, we assess the consequences of incorporation of these fatty acids on membrane lipid packing, water permeation, and membrane structure.
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Affiliation(s)
- Manuela A A Ayee
- Department of Engineering, Dordt University, Sioux Center, IA, United States.
| | - Brendan C Bunker
- Department of Engineering, Dordt University, Sioux Center, IA, United States
| | - Jordan L De Groot
- Department of Engineering, Dordt University, Sioux Center, IA, United States
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8
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Shizukuda Y, Rosing DR. Iron overload and arrhythmias: Influence of confounding factors. J Arrhythm 2019; 35:575-583. [PMID: 31410226 PMCID: PMC6686354 DOI: 10.1002/joa3.12208] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/24/2019] [Accepted: 05/15/2019] [Indexed: 12/11/2022] Open
Abstract
Arrhythmias as a cardiac complication of iron overload (IO) have been well described for decades in the clinical literature. They are assumed to be directly associated with the myocardial accumulation of iron. However, the influence of heart failure and elevated oxidative stress, which are major arrhythmogenic confounding factors associated with IO on arrhythmias, has not been critically reviewed in the published literature. A comprehensive narrative review of published articles in PubMed was conducted to address the influence of confounding factors of IO on arrhythmias. The previous data may have been largely confounded by the other cardiac complications of IO, particularly heart failure. The previous studies on IO-related arrhythmias lack proper age-gender-matched control subjects and/or comparison groups with properly controlled confounding factors to assess accurately their etiology and clinical significance. Given the above considerations, further mechanistic investigations to clarify the etiology and clinical relevance of IO-induced arrhythmias are needed. In addition, investigations to develop arrhythmia management strategy specific to IO, are warranted.
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Affiliation(s)
- Yukitaka Shizukuda
- Cardiovascular BranchNational Heart, Lung, and Blood InstituteBethesdaMaryland
- Cincinnati VA Medical CenterCincinnatiOhio
- Division of Cardiovascular Health and DiseaseUniversity of CincinnatiCincinnatiOhio
| | - Douglas R. Rosing
- Cardiovascular BranchNational Heart, Lung, and Blood InstituteBethesdaMaryland
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9
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Skogestad J, Aronsen JM. Hypokalemia-Induced Arrhythmias and Heart Failure: New Insights and Implications for Therapy. Front Physiol 2018; 9:1500. [PMID: 30464746 PMCID: PMC6234658 DOI: 10.3389/fphys.2018.01500] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 10/05/2018] [Indexed: 12/18/2022] Open
Abstract
Routine use of diuretics and neurohumoral activation make hypokalemia (serum K+ < 3. 5 mM) a prevalent electrolyte disorder among heart failure patients, contributing to the increased risk of ventricular arrhythmias and sudden cardiac death in heart failure. Recent experimental studies have suggested that hypokalemia-induced arrhythmias are initiated by the reduced activity of the Na+/K+-ATPase (NKA), subsequently leading to Ca2+ overload, Ca2+/Calmodulin-dependent kinase II (CaMKII) activation, and development of afterdepolarizations. In this article, we review the current mechanistic evidence of hypokalemia-induced triggered arrhythmias and discuss how molecular changes in heart failure might lower the threshold for these arrhythmias. Finally, we discuss how recent insights into hypokalemia-induced arrhythmias could have potential implications for future antiarrhythmic treatment strategies.
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Affiliation(s)
- Jonas Skogestad
- Division of Cardiovascular and Pulmonary Diseases, Institute of Experimental Medical Research, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Jan Magnus Aronsen
- Department of Pharmacology, Faculty of Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,Bjørknes College, Oslo, Norway
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10
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Gagliano-Jucá T, Basaria S. Response to Letter: "Effects of Testosterone Replacement on Electrocardiographic Parameters in Men: Findings From Two Randomized Trials". J Clin Endocrinol Metab 2017; 102:1788. [PMID: 28482078 DOI: 10.1210/jc.2017-00196] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 01/20/2017] [Indexed: 02/13/2023]
Affiliation(s)
- Thiago Gagliano-Jucá
- Research Program in Men's Health: Aging and Metabolism, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Shehzad Basaria
- Research Program in Men's Health: Aging and Metabolism, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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11
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Shi B, Harding S, Larsen P. Analysis of ECG Measures of Cardiac Repolarization in Relation to Arrhythmic Events in an Implantable Cardioverter Defibrillator Population. Ann Noninvasive Electrocardiol 2016; 22. [PMID: 27292910 DOI: 10.1111/anec.12390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND ECG-derived measures of cardiac repolarization may have utility in risk prediction of future ventricular arrhythmia, and a range of different measures have been proposed. We compared time-based, vectorcardiographic, and singular value decomposition (SVD) derived measures of repolarization to determine which was most predictive of appropriate therapy in an ICD population. METHODS We examined the independent prognostic value of a range of repolarization measures derived from 60 second 12-lead ECG recordings in 150 patients receiving new ICD implants in relation to the occurrence of appropriate therapy during follow-up. RESULTS Over an average follow-up of 2.15 ± 0.87 years, male gender, presence of premature ventricular complex (PVC), relative T wave residuum (TWR-rel, measures regional repolarization heterogeneity), and TCRT (the total cosine R-to-T, describes the global angle between repolarization and depolarization wavefronts) were the only independent predictors of appropriate therapy. With every 0.01% increase in TWR-rel, there was 2% increased risk of appropriate therapy (HR = 1.02, 95% CI 1.006-1.034, P < 0.001). With every 1° decrease in TCRT, there was an increase in arrhythmic risk of 0.9% (HR 1.009, 95% CI 1.003-1.015, P = 0.003). CONCLUSIONS The use of advanced analytic ECG techniques to derive measures of repolarization abnormality might shave utility in risk stratification in an ICD population.
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Affiliation(s)
- Bijia Shi
- Wellington Cardiovascular Research Group, Wellington, New Zealand.,Department of Surgery and Anaesthesia, University of Otago, Wellington, New Zealand
| | - Scott Harding
- Wellington Cardiovascular Research Group, Wellington, New Zealand.,Department of Cardiology, Wellington Regional Hospital, Wellington, New Zealand
| | - Peter Larsen
- Wellington Cardiovascular Research Group, Wellington, New Zealand.,Department of Surgery and Anaesthesia, University of Otago, Wellington, New Zealand
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12
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Gloschat CR, Koppel AC, Aras KK, Brennan JA, Holzem KM, Efimov IR. Arrhythmogenic and metabolic remodelling of failing human heart. J Physiol 2016; 594:3963-80. [PMID: 27019074 DOI: 10.1113/jp271992] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 03/21/2016] [Indexed: 12/24/2022] Open
Abstract
Heart failure (HF) is a major cause of morbidity and mortality worldwide. The global burden of HF continues to rise, with prevalence rates estimated at 1-2% and incidence approaching 5-10 per 1000 persons annually. The complex pathophysiology of HF impacts virtually all aspects of normal cardiac function - from structure and mechanics to metabolism and electrophysiology - leading to impaired mechanical contraction and sudden cardiac death. Pharmacotherapy and device therapy are the primary methods of treating HF, but neither is able to stop or reverse disease progression. Thus, there is an acute need to translate basic research into improved HF therapy. Animal model investigations are a critical component of HF research. However, the translation from cellular and animal models to the bedside is hampered by significant differences between species and among physiological scales. Our studies over the last 8 years show that hypotheses generated in animal models need to be validated in human in vitro models. Importantly, however, human heart investigations can establish translational platforms for safety and efficacy studies before embarking on costly and risky clinical trials. This review summarizes recent developments in human HF investigations of electrophysiology remodelling, metabolic remodelling, and β-adrenergic remodelling and discusses promising new technologies for HF research.
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Affiliation(s)
- C R Gloschat
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - A C Koppel
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - K K Aras
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - J A Brennan
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - K M Holzem
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
| | - I R Efimov
- Department of Biomedical Engineering, The George Washington University, Washington, DC, USA
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13
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Boulaksil M, Bierhuizen MFA, Engelen MA, Stein M, Kok BJM, van Amersfoorth SCM, Vos MA, van Rijen HVM, de Bakker JMT, van Veen TAB. Spatial Heterogeneity of Cx43 is an Arrhythmogenic Substrate of Polymorphic Ventricular Tachycardias during Compensated Cardiac Hypertrophy in Rats. Front Cardiovasc Med 2016; 3:5. [PMID: 26973841 PMCID: PMC4773605 DOI: 10.3389/fcvm.2016.00005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/18/2016] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Ventricular remodeling increases the propensity of ventricular tachyarrhythmias and sudden death in patients. We studied the mechanism underlying these fatal arrhythmias, electrical and structural cardiac remodeling, as well as arrhythmogeneity during early, compensated hypertrophy in a rat model of chronic pressure overload. METHODS Twenty-six Wistar rats were subjected to transverse aortic constriction (TAC) (n = 13) or sham operation (n = 13). Four weeks postoperative, echo- and electrocardiography was performed. Epicardial (208 or 455 sites) and transmural (30 sites) ventricular activation mapping was performed on Langendorff perfused hearts. Subsequently, hearts were processed for (immuno)histological and molecular analyses. RESULTS TAC rats showed significant hypertrophy with preserved left ventricular (LV) function. Epicardial conduction velocity (CV) was similar, but more dispersed in TAC. Transmural CV was slowed in TAC (37.6 ± 2.9 cm s(-1)) compared to sham (58.5 ± 3.9 cm s(-1); P < 0.01). Sustained polymorphic ventricular tachycardias were induced from LV in 8/13 TAC and in 0/13 sham rats. During VT, electrical activation patterns showed variable sites of earliest epicardial activation and altering sites of functional conduction block. Wandering epicardial reentrant activation was sporadically observed. Collagen deposition was significantly higher in TAC compared to sham, but not different between arrhythmogenic and non-arrhythmogenic TAC animals. Connexin43 (Cx43) expression was heterogeneous with a higher prevalence of non-phosphorylated Cx43 in arrhythmogenic TAC animals. CONCLUSION In TAC rats with compensated cardiac hypertrophy, dispersion of conduction correlated to arrhythmogenesis, an increased heterogeneity of Cx43, and a partial substitution with non-phosphorylated Cx43. These alterations may result in the increased vulnerability to polymorphic VTs.
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Affiliation(s)
- Mohamed Boulaksil
- Interuniversity Cardiology Institute of the Netherlands, Utrecht, Netherlands; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands; Department of Cardiology, Radboud University Medical Center, Nijmegen, Netherlands
| | - Marti F A Bierhuizen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
| | - Markus A Engelen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands; Division of Cardiology, Department of Cardiovascular Medicine, University of Muenster, Muenster, Germany
| | - Mèra Stein
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands; Division of Heart and Lungs, Department of Cardiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Bart J M Kok
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
| | | | - Marc A Vos
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
| | - Harold V M van Rijen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
| | - Jacques M T de Bakker
- Interuniversity Cardiology Institute of the Netherlands, Utrecht, Netherlands; Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands; Heart Failure Research Center, Academic Medical Center, Amsterdam, Netherlands
| | - Toon A B van Veen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht , Utrecht , Netherlands
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Tolouee A, Alirezaie J, Babyn P. Compressed sensing reconstruction of cardiac cine MRI using golden angle spiral trajectories. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 260:10-19. [PMID: 26397216 DOI: 10.1016/j.jmr.2015.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 08/31/2015] [Accepted: 09/01/2015] [Indexed: 06/05/2023]
Abstract
In dynamic cardiac cine Magnetic Resonance Imaging (MRI), the spatiotemporal resolution is limited by the low imaging speed. Compressed sensing (CS) theory has been applied to improve the imaging speed and thus the spatiotemporal resolution. The purpose of this paper is to improve CS reconstruction of under sampled data by exploiting spatiotemporal sparsity and efficient spiral trajectories. We extend k-t sparse algorithm to spiral trajectories to achieve high spatio temporal resolutions in cardiac cine imaging. We have exploited spatiotemporal sparsity of cardiac cine MRI by applying a 2D+time wavelet-Fourier transform. For efficient coverage of k-space, we have used a modified version of multi shot (interleaved) spirals trajectories. In order to reduce incoherent aliasing artifact, we use different random undersampling pattern for each temporal frame. Finally, we have used nonuniform fast Fourier transform (NUFFT) algorithm to reconstruct the image from the non-uniformly acquired samples. The proposed approach was tested in simulated and cardiac cine MRI data. Results show that higher acceleration factors with improved image quality can be obtained with the proposed approach in comparison to the existing state-of-the-art method. The flexibility of the introduced method should allow it to be used not only for the challenging case of cardiac imaging, but also for other patient motion where the patient moves or breathes during acquisition.
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Affiliation(s)
- Azar Tolouee
- Department of Electrical and Computer Engineering, Ryerson University, Toronto, Ontario, Canada
| | - Javad Alirezaie
- Department of Electrical and Computer Engineering, Ryerson University, Toronto, Ontario, Canada.
| | - Paul Babyn
- Department of Medical Imaging, University of Saskatoon Health Region, Royal University Hospital, Saskatoon, Canada
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15
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Akar FG, Hajjar RJ. Gene therapies for arrhythmias in heart failure. Pflugers Arch 2014; 466:1211-7. [PMID: 24566976 DOI: 10.1007/s00424-014-1485-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 01/16/2023]
Abstract
In this article, we review recent advances in our understanding of arrhythmia mechanisms in the failing heart. We focus on changes in repolarization, conduction, and intracellular calcium cycling because of their importance to the vast majority of clinical arrhythmias in heart failure. We highlight recent efforts to combat arrhythmias using gene-based approaches that target ion channel, gap junction, and calcium cycling proteins. We further discuss the advantages and limitations associated with individual approaches.
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Affiliation(s)
- Fadi G Akar
- The Cardiovascular Research Center, Mount Sinai School of Medicine, New York, NY, USA,
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16
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Speerschneider T, Thomsen MB. Physiology and analysis of the electrocardiographic T wave in mice. Acta Physiol (Oxf) 2013; 209:262-71. [PMID: 24119104 DOI: 10.1111/apha.12172] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 08/20/2013] [Accepted: 09/24/2013] [Indexed: 01/28/2023]
Abstract
AIM The murine electrocardiogram (ECG) is a valuable tool in cardiac research, although the definition of the T wave has been a matter of debate for several years potentially leading to incomparable data. By this study, we seek to make a clear definition of the murine T wave. Moreover, we investigate the consequences of performing QT interval correction in anaesthetized mice. METHODS Electrocardiograms from conscious mice were recorded by implanted telemetry devices. Surface ECGs were recorded from anaesthetized mice before and during pharmacological interventions, ventricular ischaemia and heart failure. Right atrial pacing was performed to evaluate the relationship between heart rate and QT intervals. RESULTS Electrocardiogram traces of conscious and anaesthetized mice (lead II) showed separable positive J waves and negative T waves. The end of the T wave was determined as the point where the T wave returned to the isoelectric line. Atrial pacing revealed that the duration of the QT interval is independent of heart rate in anaesthetized mice. The calcium channel blocker, verapamil, prolonged the PR interval; however, the polarities of the J and T waves were not changed. Local cardiac ischaemia and β-adrenergic stimulation caused indistinguishable positive J and T waves. In contrast, chronic heart failure caused entirely negative J and T waves. In every case, the end of the T wave was clearly distinguishable on the ECG. CONCLUSION The end of the T wave is readily available from conscious and anaesthetized mice. Heart rate correction of QT interval duration in the anaesthetized mouse is not recommended.
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Affiliation(s)
- T. Speerschneider
- Department of Biomedical Sciences; Faculty of Health and Medical Sciences; Danish National Research Foundation Centre for Cardiac Arrhythmia; University of Copenhagen; Copenhagen Denmark
| | - M. B. Thomsen
- Department of Biomedical Sciences; Faculty of Health and Medical Sciences; Danish National Research Foundation Centre for Cardiac Arrhythmia; University of Copenhagen; Copenhagen Denmark
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17
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Saito T, Hojo Y, Hirose M, Ikemoto T, Katsuki T, Kario K. High-sensitivity troponin T is a prognostic marker for patients with aortic stenosis after valve replacement surgery. J Cardiol 2013; 61:342-7. [DOI: 10.1016/j.jjcc.2013.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 12/25/2012] [Accepted: 01/07/2013] [Indexed: 01/28/2023]
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Holzem KM, Efimov IR. Arrhythmogenic remodelling of activation and repolarization in the failing human heart. Europace 2013; 14 Suppl 5:v50-v57. [PMID: 23104915 DOI: 10.1093/europace/eus275] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Heart failure is a major cause of disability and death worldwide, and approximately half of heart failure-related deaths are sudden and presumably due to ventricular arrhythmias. Patients with heart failure have been shown to be at 6- to 9-fold increased risk of sudden cardiac death compared to the general population. (AHA. Heart Disease and Stroke Statistics-2003 Update. Heart and Stroke Facts. Dallas, TX: American Heart Association; 2002) Thus, electrophysiological remodelling associated with heart failure is a leading cause of disease mortality and has been a major investigational focus examined using many animal models of heart failure. While these studies have provided an important foundation for understanding the arrhythmogenic pathophysiology of heart failure, the need for corroborating studies conducted on human heart tissue has been increasingly recognized. Many human heart studies of conduction and repolarization remodelling have now been published and shed some light on important, potentially arrhythmogenic, changes in human heart failure. These studies are being conducted at multiple experimental scales from isolated cells to whole-tissue preparations and have provided insight into regulatory mechanisms such as decreased protein expression, alternative mRNA splicing of ion channel genes, and defective cellular trafficking. Further investigations of heart failure in the human myocardium will be essential for determining possible therapeutic targets to prevent arrhythmia in heart failure and for facilitating the translation of basic research findings to the clinical realm.
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Affiliation(s)
- Katherine M Holzem
- Department of Biomedical Engineering, Washington University in St Louis, One Brookings Drive, St Louis, MO 63130, USA
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19
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Piccirillo G, Rossi P, Mitra M, Quaglione R, Dell'Armi A, Di Barba D, Maisto D, Lizio A, Barillà F, Magrì D. Indexes of temporal myocardial repolarization dispersion and sudden cardiac death in heart failure: any difference? Ann Noninvasive Electrocardiol 2012; 18:130-9. [PMID: 23530483 DOI: 10.1111/anec.12005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The QT variability index, calculated between Q- and the T-wave end (QTend VI), is an index of temporal myocardial repolarization lability associated with sudden cardiac death (SCD) in chronic heart failure (CHF). Little is known about temporal variability in the other two temporal myocardial repolarization descriptors obtained from Q-Tpeak and Tpeak -Tend intervals. We therefore investigated differences between these indexes in patients with CHF who died suddenly and in those who survived with a left ventricular ejection fraction (LVEF) ≤35% or >35%. METHODS AND RESULTS We selected 127 ECG and systolic blood pressure (SPB) recordings from outpatients with CHF all of whom had been followed up for 30 months. We calculated RR and SPB variability by power spectral analysis and QTend VI, QTpeak VI, Tpeak Tend VI. We then subdivided data patients into three groups SCD, LVEF ≤ 35%, and LVEF > 35%. The LVEF was higher in the SCD than in the LVEF ≤ 35% group, whereas no difference was found between the SCD and LVEF > 35% groups. QTend VI, QTpeak VI, and Tpeak Tend VI were higher in the SCD and LVEF ≤ 35% groups than in the LVEF > 35% group. Multivariate analysis detected a negative relationship between all repolarization variability indexes, low frequency obtained from RR intervals and LVEF. CONCLUSIONS Our data show that variability in the first (QTpeak VI) and second halves of the QT interval (Tpeak -Tend VI) significantly contributes to the QTend VI in patients with CHF. Further studies should investigate whether these indexes might help stratify the risk of SCD in patients with a moderately depressed LVEF.
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Affiliation(s)
- Gianfranco Piccirillo
- Department of Cardiovascular, Respiratory, Nephrologic, and Geriatric Sciences, Sapienza University of Rome, 00185 Rome, Italy.
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Calcific aortic stenosis: a disease of the valve and the myocardium. J Am Coll Cardiol 2012; 60:1854-63. [PMID: 23062541 DOI: 10.1016/j.jacc.2012.02.093] [Citation(s) in RCA: 435] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/31/2012] [Accepted: 02/14/2012] [Indexed: 02/07/2023]
Abstract
Although aortic stenosis is a common condition associated with major morbidity, mortality, and health economic costs, there are currently no medical interventions capable of delaying or halting its progression. Re-evaluation of the underlying pathophysiology is therefore required so that novel therapeutic strategies can be developed. Aortic stenosis is characterized by progressive aortic valve narrowing and secondary left ventricular hypertrophy. Both processes are important because in combination they drive the development of symptoms and adverse events that characterize the latter stages of the disease. In this review, the authors examine the pathophysiology of aortic stenosis with respect to both the valve and the myocardium. In particular, the authors focus on the role of inflammation, fibrosis, and calcification in progressive valve narrowing and then examine the development of left ventricular hypertrophy, its subsequent decompensation, and the transition to heart failure. Finally the authors discuss potential therapeutic strategies on the basis of similarities aortic stenosis shares with other pathological conditions.
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Cherry EM, Fenton FH, Gilmour RF. Mechanisms of ventricular arrhythmias: a dynamical systems-based perspective. Am J Physiol Heart Circ Physiol 2012; 302:H2451-63. [PMID: 22467299 PMCID: PMC3378269 DOI: 10.1152/ajpheart.00770.2011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 03/26/2012] [Indexed: 01/23/2023]
Abstract
Defining the cellular electrophysiological mechanisms for ventricular tachyarrhythmias is difficult, given the wide array of potential mechanisms, ranging from abnormal automaticity to various types of reentry and kk activity. The degree of difficulty is increased further by the fact that any particular mechanism may be influenced by the evolving ionic and anatomic environments associated with many forms of heart disease. Consequently, static measures of a single electrophysiological characteristic are unlikely to be useful in establishing mechanisms. Rather, the dynamics of the electrophysiological triggers and substrates that predispose to arrhythmia development need to be considered. Moreover, the dynamics need to be considered in the context of a system, one that displays certain predictable behaviors, but also one that may contain seemingly stochastic elements. It also is essential to recognize that even the predictable behaviors of this complex nonlinear system are subject to small changes in the state of the system at any given time. Here we briefly review some of the short-, medium-, and long-term alterations of the electrophysiological substrate that accompany myocardial disease and their potential impact on the initiation and maintenance of ventricular arrhythmias. We also provide examples of cases in which small changes in the electrophysiological substrate can result in rather large differences in arrhythmia outcome. These results suggest that an interrogation of cardiac electrical dynamics is required to provide a meaningful assessment of the immediate risk for arrhythmia development and for evaluating the effects of putative antiarrhythmic interventions.
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Affiliation(s)
- Elizabeth M Cherry
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853-6401, USA
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22
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Johnson CM, Pogwizd SM. Focal initiation of sustained and nonsustained ventricular tachycardia in a canine model of ischemic cardiomyopathy. J Cardiovasc Electrophysiol 2011; 23:543-52. [PMID: 22175759 DOI: 10.1111/j.1540-8167.2011.02239.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION To define the role of focal and reentrant mechanisms underlying nonsustained (NSVT) and sustained ventricular tachycardia (SuVT) induced by programmed stimulation, 3-dimensional cardiac mapping was performed in 8 dogs with heart failure (HF) created by multiple intracoronary microsphere embolizations. METHODS AND RESULTS Continuous recording from 232 intramural sites throughout the left and right ventricles and the interventricular septum was performed during programmed stimulation in the absence and presence of isoproterenol (Iso, 0.1 μg/kg/min). Sinus beats and the last extrastimuli preceding induced VT conducted with total activation times (TA) of 51 ± 10 and 111 ± 8 milliseconds, respectively, that did not change during Iso infusion (47 ± 4 and 109 ± 5 milliseconds, P = NS). NSVT was induced in 75% of HF dogs; SuVT was induced in 38%. In all cases, initiation and maintenance of SuVT and NSVT arose by a focal mechanism. Compared to NSVT, SuVT had a shorter coupling interval (CI; 150 ± 7 vs 186 ± 16, P < 0.05) and a predilection for certain critical subendocardial initiation sites (that were initiation sites for only 29% of NSVT beats). After 21-30 beats, acceleration of SuVT by a focal mechanism to a CI less than 120 milliseconds led to functional conduction delay (TA increasing from 111 ± 3 to 137 ± 3 milliseconds, P < 0.0001), intramural reentry, and transition to ventricular fibrillation. CONCLUSIONS Thus, initiation of SuVT in a model of ischemic HF is due to a focal mechanism. However, subsequent acceleration of this focal mechanism can ultimately lead to functional conduction delay and development of intramural reentry.
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Affiliation(s)
- Carolyn M Johnson
- Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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Dweck MR, Joshi S, Murigu T, Alpendurada F, Jabbour A, Melina G, Banya W, Gulati A, Roussin I, Raza S, Prasad NA, Wage R, Quarto C, Angeloni E, Refice S, Sheppard M, Cook SA, Kilner PJ, Pennell DJ, Newby DE, Mohiaddin RH, Pepper J, Prasad SK. Midwall fibrosis is an independent predictor of mortality in patients with aortic stenosis. J Am Coll Cardiol 2011; 58:1271-9. [PMID: 21903062 DOI: 10.1016/j.jacc.2011.03.064] [Citation(s) in RCA: 393] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Revised: 03/08/2011] [Accepted: 03/17/2011] [Indexed: 12/14/2022]
Abstract
OBJECTIVES The goal of this study was to assess the prognostic significance of midwall and infarct patterns of late gadolinium enhancement (LGE) in aortic stenosis. BACKGROUND Myocardial fibrosis occurs in aortic stenosis as part of the hypertrophic response. It can be detected by LGE, which is associated with an adverse prognosis in a range of other cardiac conditions. METHODS Between January 2003 and October 2008, consecutive patients with moderate or severe aortic stenosis undergoing cardiovascular magnetic resonance with administration of gadolinium contrast were enrolled into a registry. Patients were categorized into absent, midwall, or infarct patterns of LGE by blinded independent observers. Patient follow-up was completed using patient questionnaires, source record data, and the National Strategic Tracing Service. RESULTS A total of 143 patients (age 68 ± 14 years; 97 male) were followed up for 2.0 ± 1.4 years. Seventy-two underwent aortic valve replacement, and 27 died (24 cardiac, 3 sudden cardiac deaths). Compared with those with no LGE (n = 49), univariate analysis revealed that patients with midwall fibrosis (n = 54) had an 8-fold increase in all-cause mortality despite similar aortic stenosis severity and coronary artery disease burden. Patients with an infarct pattern (n = 40) had a 6-fold increase. Midwall fibrosis (hazard ratio: 5.35; 95% confidence interval: 1.16 to 24.56; p = 0.03) and ejection fraction (hazard ratio: 0.96; 95% confidence interval: 0.94 to 0.99; p = 0.01) were independent predictors of all-cause mortality by multivariate analysis. CONCLUSIONS Midwall fibrosis was an independent predictor of mortality in patients with moderate and severe aortic stenosis. It has incremental prognostic value to ejection fraction and may provide a useful method of risk stratification.
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Jeong EM, Liu M, Sturdy M, Gao G, Varghese ST, Sovari AA, Dudley SC. Metabolic stress, reactive oxygen species, and arrhythmia. J Mol Cell Cardiol 2011; 52:454-63. [PMID: 21978629 DOI: 10.1016/j.yjmcc.2011.09.018] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Revised: 08/20/2011] [Accepted: 09/19/2011] [Indexed: 02/07/2023]
Abstract
Cardiac arrhythmias can cause sudden cardiac death (SCD) and add to the current heart failure (HF) health crisis. Nevertheless, the pathological processes underlying arrhythmias are unclear. Arrhythmic conditions are associated with systemic and cardiac oxidative stress caused by reactive oxygen species (ROS). In excitable cardiac cells, ROS regulate both cellular metabolism and ion homeostasis. Increasing evidence suggests that elevated cellular ROS can cause alterations of the cardiac sodium channel (Na(v)1.5), abnormal Ca(2+) handling, changes of mitochondrial function, and gap junction remodeling, leading to arrhythmogenesis. This review summarizes our knowledge of the mechanisms by which ROS may cause arrhythmias and discusses potential therapeutic strategies to prevent arrhythmias by targeting ROS and its consequences. This article is part of a Special Issue entitled "Local Signaling in Myocytes".
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Affiliation(s)
- Euy-Myoung Jeong
- Section of Cardiology, University of Illinois at Chicago, Chicago, IL 60612, USA.
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Increased left ventricular mass and decreased left ventricular systolic function have independent pathways to ventricular arrhythmogenesis in coronary artery disease. Heart Rhythm 2011; 8:1177-82. [PMID: 21376836 DOI: 10.1016/j.hrthm.2011.02.037] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 02/25/2011] [Indexed: 01/19/2023]
Abstract
BACKGROUND Following myocardial infarction, individual patients can have wide variations in the extent of left ventricular systolic dysfunction (LVSD) and increased left ventricular (LV) mass. Both affect the risk for sudden cardiac death, but only LV ejection fraction is used for risk prediction. OBJECTIVE The purpose of this study was to evaluate the independent as well as the additive contributions of increased LV mass and decreased LV ejection fraction to sudden cardiac death in the general population. METHODS In the ongoing Oregon Sudden Unexpected Death Study, we studied consecutive SCD cases (n = 191) and coronary artery disease controls (n = 203) from the Portland, Oregon, metropolitan area (population approximately 1,000,000; 2002-2008). Comparisons of echocardiographic LV mass obtained prior and unrelated to sudden cardiac death (SCD) were conducted, and a logistic regression model was used to evaluate the relationship between SCD, severe LVSD, LV mass, and other relevant clinical variables. RESULTS In a multivariate model, both severe LVSD and left ventricular hypertrophy (LVH) were associated with increased SCD risk (odds ratio [OR] 1.9, 95% confidence interval [CI] 1.1-3.2 for severe LVSD; OR 1.8, 95% CI 1.1-2.9 for LVH). In patients with coexisting severe LVSD and LVH, risk of SCD was additive (OR 3.5, 95% CI 1.7-7.2). In the same model, increased age, atrial fibrillation/flutter, elevated creatinine, and diabetes independently increased risk, and use of angiotensin receptor blockers attenuated risk. CONCLUSION Reduced LV ejection fraction and increased LV mass had independent and additive effects on risk of sudden death. Despite the significant overlap between the two conditions, these findings point toward the existence of independent mechanistic pathways for ventricular arrhythmias that occur due to LVSD and LVH.
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Salama G, Akar FG. Deciphering Arrhythmia Mechanisms - Tools of the Trade. Card Electrophysiol Clin 2011; 3:11-21. [PMID: 21572551 PMCID: PMC3093299 DOI: 10.1016/j.ccep.2010.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Pathophysiological remodeling of cardiac function occurs at multiple levels, spanning the spectrum from molecular and sub-cellular changes to those occurring at the organ-system levels. Of key importance to arrhythmias are changes in electrophysiological and calcium handling properties at the tissue level. In this review, we discuss how high-resolution optical action potential and calcium transient imaging has advanced our understanding of basic arrhythmia mechanisms associated with multiple cardiovascular disorders, including the long QT syndrome, heart failure, and ischemia-reperfusion injury. We focus on the role of repolarization gradients (section 1) and calcium mediated triggers (section 2) in the initiation and maintenance of complex arrhythmias in these settings.
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Affiliation(s)
- Guy Salama
- University of Pittsburgh, The Cardiovascular Institute, Pittsburgh, PA, 15261
| | - Fadi G. Akar
- Mount Sinai School of Medicine, New York, NY 10029, Tel: 212-241-9251; FAX: 212-241-4080
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Sharif B, Derbyshire JA, Faranesh AZ, Bresler Y. Patient-adaptive reconstruction and acquisition in dynamic imaging with sensitivity encoding (PARADISE). Magn Reson Med 2011; 64:501-13. [PMID: 20665794 DOI: 10.1002/mrm.22444] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
MRI of the human heart without explicit cardiac synchronization promises to extend the applicability of cardiac MR to a larger patient population and potentially expand its diagnostic capabilities. However, conventional nongated imaging techniques typically suffer from low image quality or inadequate spatio-temporal resolution and fidelity. Patient-Adaptive Reconstruction and Acquisition in Dynamic Imaging with Sensitivity Encoding (PARADISE) is a highly accelerated nongated dynamic imaging method that enables artifact-free imaging with high spatio-temporal resolutions by utilizing novel computational techniques to optimize the imaging process. In addition to using parallel imaging, the method gains acceleration from a physiologically driven spatio-temporal support model; hence, it is doubly accelerated. The support model is patient adaptive, i.e., its geometry depends on dynamics of the imaged slice, e.g., subject's heart rate and heart location within the slice. The proposed method is also doubly adaptive as it adapts both the acquisition and reconstruction schemes. Based on the theory of time-sequential sampling, the proposed framework explicitly accounts for speed limitations of gradient encoding and provides performance guarantees on achievable image quality. The presented in-vivo results demonstrate the effectiveness and feasibility of the PARADISE method for high-resolution nongated cardiac MRI during short breath-hold.
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Affiliation(s)
- Behzad Sharif
- Department of Electrical and Computer Engineering and Coordinated Science Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
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Li LD, Zhang CT, Ruan L, Ni MK, Quan XQ. Gap junctions enhancer combined with Vaughan Williams class III antiarrhythmic drugs, a promising antiarrhythmic method? Med Hypotheses 2010; 76:119-21. [PMID: 20889260 DOI: 10.1016/j.mehy.2010.08.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 08/24/2010] [Accepted: 08/27/2010] [Indexed: 11/18/2022]
Abstract
Arrhythmias is one of the leading causes of death in the world. Current antiarrhythmic drugs are limited by unsatisfactory efficacy and adverse effects such as proarrhythmias. Reentry mechanism plays an important role in persistence of arrhythmias. Reentry can only continue when reentry path-length is longer than cardiac wavelength which is equal to the product of conduction velocity (CV) and effective refractory period (ERP). Gap junctions uncoupling is associated with proarrhythmic CV slowing and transmural dispersion of repolarization (TDR) increasing in many cardiac diseases. Vaughan Williams class III antiarrhythmic drugs prolong ERP with an augmented TDR which is the main mechanism of the proarrhythmic effects. Gap junctions enhancer can augment CV and diminish TDR. As a result, gap junctions enhancer combined with class III drugs may be a promising antiarrhythmic method.
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Affiliation(s)
- Lian-dong Li
- Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China
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Hinterseer M, Beckmann BM, Thomsen MB, Pfeufer A, Ulbrich M, Sinner MF, Perz S, Wichmann HE, Lengyel C, Schimpf R, Maier SK, Varró A, Vos MA, Steinbeck G, Kääb S. Usefulness of short-term variability of QT intervals as a predictor for electrical remodeling and proarrhythmia in patients with nonischemic heart failure. Am J Cardiol 2010; 106:216-20. [PMID: 20599006 DOI: 10.1016/j.amjcard.2010.02.033] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Revised: 02/24/2010] [Accepted: 02/24/2010] [Indexed: 10/19/2022]
Abstract
The high incidence of sudden cardiac death in heart failure (HF) reflects electrophysiologic changes in response to myocardial failure. We previously showed that short-term variability of QT intervals (STV(QT)) identifies latent repolarization disorders in patients with drug-induced or congenital long QT syndrome. This study sought to determine (1) if STV(QT) is increased in patients with dilated cardiomyopathy (DC) and moderate congestive HF and (2) if increased STV(QT) is associated with ventricular arrhythmia in patients with HF. Sixty patients (53 +/- 12 years of age, 14 women) with DC and moderate HF (New York Heart Association classes II to III) were compared to matched controls. Twenty patients had implantable cardiac defibrillators secondary to a history of ventricular tachycardia (VT). Two cardiologists blinded to diagnosis manually measured QT intervals. Beat-to-beat variability of repolarization was determined from Poincaré plots of 30 consecutive QT intervals as was STV(QT). QTc intervals were comparable in patients and controls (419 +/- 36 vs 415 +/- 32 ms, respectively, p >0.05), whereas STV(QT) was significantly higher in patients with HF (7.8 +/- 3 vs 4.1 +/- 2 ms, respectively, p <0.05). STV(QT) was more increased in patients with a history of VT compared to those without VT (10.1 +/- 2 vs 6.6 +/- 2 ms, respectively, p <0.05). Increased STV(QT) and decreased ejection fraction were associated with a history of VT; however, STV(QT) was the strongest indicator. In conclusion, the present study demonstrates for the first time that STV(QT) is increased in patients with DC with HF. Patients with DC and HF and implantable cardiac defibrillators for secondary prevention had the highest STV(QT). Thus, increased STV(QT) in the context of moderate HF may reflect a latent repolarization disorder and increased susceptibility to sudden death in patients with DC, which is not identified by a prolonged QT interval.
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Miura M, Nishio T, Hattori T, Murai N, Stuyvers BD, Shindoh C, Boyden PA. Effect of nonuniform muscle contraction on sustainability and frequency of triggered arrhythmias in rat cardiac muscle. Circulation 2010; 121:2711-7. [PMID: 20547931 DOI: 10.1161/circulationaha.109.907717] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Arrhythmias are benign or lethal, depending on their sustainability and frequency. To determine why lethal arrhythmias are prone to occur in diseased hearts, usually characterized by nonuniform muscle contraction, we investigated the effect of nonuniformity on sustainability and frequency of triggered arrhythmias. METHODS AND RESULTS Force, membrane potential, and intracellular Ca(2+) concentration ([Ca(2+)](i)) were measured in 51 rat ventricular trabeculae. Nonuniform contraction was produced by exposing a restricted region of muscle to a jet of 20 mmol/L 2,3-butanedione monoxime (BDM) or 20 mumol/L blebbistatin. Sustained arrhythmias (>10 seconds) could be induced by stimulus trains for 7.5 seconds only with the BDM or blebbistatin jet (100 nmol/L isoproterenol, 1.0 mmol/L [Ca(2+)](o), 24 degrees C). During sustained arrhythmias, Ca(2+) surges preceded synchronous increases in [Ca(2+)](i), whereas the stoppage of the BDM jet made the Ca(2+) surges unclear and arrested sustained arrhythmias (n=6). With 200 nmol/L isoproterenol, 2.5 mmol/L [Ca(2+)](o), and the BDM jet, lengthening or shortening of the muscle during sustained arrhythmias accelerated or decelerated their cycle in both the absence (n=10) and presence (n=10) of 100 mumol/L streptomycin, a stretch-activated channel blocker, respectively. The maximum rate of force relaxation correlated inversely with the change in cycle lengths (n=14; P<0.01). Sustained arrhythmias with the BDM jet were significantly accelerated by 30 mumol/L SCH00013, a Ca(2+) sensitizer of myofilaments (n=10). CONCLUSIONS These results suggest that nonuniformity of muscle contraction is an important determinant of the sustainability and frequency of triggered arrhythmias caused by the surge of Ca(2+) dissociated from myofilaments in cardiac muscle.
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Affiliation(s)
- Masahito Miura
- Department of Clinical Physiology, Health Science, Tohoku University Graduate School of Medicine, Sendai, Japan.
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Hebert K, Lopez B, Dias A, Steen DL, Colombo RA, Franco E, Neistein S, Arcement LM. Prevalence of electrocardiographic abnormalities in a systolic heart failure disease management population by race, ethnicity, and sex. ACTA ACUST UNITED AC 2010; 16:21-6. [PMID: 20078624 DOI: 10.1111/j.1751-7133.2009.00126.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The prevalence of electrocardiographic (ECG) abnormalities in systolic heart failure patients have predominantly been described in white patients, with relatively little known about their prevalence in black and Hispanic populations. The purpose of this study is to compare the prevalence of ECG abnormalities by race, ethnicity, and sex. The authors conducted an observational prospective study that included 926 patients from 2 hospital facilities. A systolic heart failure disease management program implemented in both sites enrolled patients with an ejection fraction < or =40% by echocardiography. Black patients had less evidence of myocardial infarction than whites and Hispanics. Black patients had more evidence of left ventricular hypertrophy than Hispanics and whites. Hispanics evidenced more ischemic changes than blacks and whites. Among black patients, left ventricular hypertrophy was more prevalent in women. ECG abnormalities vary across race, ethnicity, and sex. These variations may have implications for further diagnostic testing and potential treatment regimens.
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Kontaraki JE, Parthenakis FI, Nyktari EG, Patrianakos AP, Vardas PE. Myocardial gene expression alterations in peripheral blood mononuclear cells of patients with idiopathic dilated cardiomyopathy. Eur J Heart Fail 2010; 12:541-8. [PMID: 20388650 DOI: 10.1093/eurjhf/hfq057] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AIMS To assess cardiac gene expression in peripheral blood cells of patients with idiopathic dilated cardiomyopathy (IDCM) and its relationship to echocardiographic left ventricular (LV) function. METHODS AND RESULTS A complete echocardiographic study and blood sampling were performed in 65 consecutive stable IDCM patients with LV ejection fraction (LVEF) 31.76 +/- 10.07% and chronic mild to moderate heart failure (NYHA functional class II to III) for > or =9 months. Blood samples from 19 healthy individuals were included for comparison. Transcript levels of myocardin, GATA4, alpha- and beta-myosin heavy chain (MHC), sarcoplasmic reticulum calcium ATPase 2 (SERCA2), and phospholamban were determined by quantitative real-time reverse transcription-polymerase chain reaction. Myocardin (24.88 +/- 4.93 vs. 3.98 +/- 1.12, P = 0.0048) and GATA4 (17.85 +/- 4.85 vs. 0.45 +/- 0.15, P = 0.0069 x 10(-5)) were upregulated in IDCM patients compared with controls, whereas SERCA2 (5.11 +/- 0.42 vs. 8.93 +/- 1.07, P = 0.001) was downregulated. In IDCM patients, myocardin (r = 0.279, P = 0.025), GATA4 (r = 0.314, P = 0.011), beta-MHC (r = 0.444, P=0.0002), and alpha-MHC (r = 0.272, P = 0.034) showed positive correlations, whereas SERCA2 (r = -0.264, P = 0.034) exhibited a negative correlation with LVEF. Patients with elevated LV filling pressures had lower myocardin (15.06 +/- 3.10 vs. 43.12 +/- 12.03, P = 0.048), GATA4 (8.96 +/- 2.17 vs. 34.38 +/- 12.60, P = 0.026), beta-MHC (10.59 +/- 4.05 vs. 16.43 +/- 4.91, P = 0.013), and alpha-MHC (0.27 +/- 0.08 vs. 0.79 +/- 0.20, P = 0.033) and higher SERCA2 (5.65 +/- 0.54 vs. 3.90 +/- 0.61, P = 0.037) levels. Patients with atrial fibrillation (AF) had higher SERCA2 levels compared with sinus rhythm patients (6.75 +/- 0.84 vs. 4.54 +/- 0.45, P = 0.017). CONCLUSION Our data indicate that cardiac gene expression alterations in peripheral blood cells of IDCM patients may reflect alterations in LV function, whereas the presence of AF may be associated with increased SERCA2 levels in these patients.
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Affiliation(s)
- Joanna E Kontaraki
- Molecular Cardiology Laboratory, School of Medicine, University of Crete, Crete, Greece.
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de Haan S, Knaapen P, Beek AM, de Cock CC, Lammertsma AA, van Rossum AC, Allaart CP. Risk stratification for ventricular arrhythmias in ischaemic cardiomyopathy: the value of non-invasive imaging. Europace 2010; 12:468-74. [DOI: 10.1093/europace/euq064] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Guo D, Young L, Wu Y, Belardinelli L, Kowey PR, Yan GX. Increased late sodium current in left atrial myocytes of rabbits with left ventricular hypertrophy: its role in the genesis of atrial arrhythmias. Am J Physiol Heart Circ Physiol 2010; 298:H1375-81. [PMID: 20190097 DOI: 10.1152/ajpheart.01145.2009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Left ventricular hypertrophy (LVH) is frequently associated with clinical atrial arrhythmias, but little is known about how it causes those arrhythmias. Our previous studies have shown that LVH increases the late sodium current (I(Na-L)) that plays an important role in the genesis of ventricular arrhythmias. We hypothesize that LVH may also induce an upregulation of the I(Na-L) in atrial myocytes, leading to atrial electrical abnormalities. The renovascular hypertension model was used to induce LVH in rabbits. Action potential and membrane current recordings were performed in single myocytes. At a pacing cycle length of 2,000 ms, spontaneous phase-2 early afterdepolarizations (EADs) could be recorded from the left atrial myocytes in 10 of 12 LVH rabbits, whereas no EADs could be elicited in right atrial myocytes of LVH rabbits or atrial myocytes from any of the 12 control rabbits. Spontaneous automaticity (SA) from left atrial myocytes was observed in 9 out of 12 LVH rabbits, but none in right atrial myocytes of LVH rabbits or control rabbits, at a pacing rate of 8,000 ms. The left atrial myocytes of LVH rabbits had a significantly higher density of the I(Na-L) compared with those of control rabbits (0.90 +/- 0.12 in LVH vs. 0.50 +/- 0.08 pA/pF in control, n = 8, P < 0.01). Tetrodotoxin, an I(Na-L) blocker, abolished all atrial EADs and SA at 10 microM. Our results demonstrate that LVH induction results in a significant increase of I(Na-L) in the left atrial myocytes that may render these cells susceptible to the genesis of EADs and SA. The I(Na-L) may serve as a potentially useful ionic target for antiarrhythmic drugs for the treatment of atrial arrhythmias in the setting of LVH.
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Affiliation(s)
- Donglin Guo
- Main Line Health Heart Center & Lankenau Inst., Medical Research, 100 Lancaster Ave., Wynnewood, PA 19096, USA.
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Glukhov AV, Fedorov VV, Lou Q, Ravikumar VK, Kalish PW, Schuessler RB, Moazami N, Efimov IR. Transmural dispersion of repolarization in failing and nonfailing human ventricle. Circ Res 2010; 106:981-91. [PMID: 20093630 DOI: 10.1161/circresaha.109.204891] [Citation(s) in RCA: 223] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
RATIONALE Transmural dispersion of repolarization has been shown to play a role in the genesis of ventricular tachycardia and fibrillation in different animal models of heart failure (HF). Heterogeneous changes of repolarization within the midmyocardial population of ventricular cells have been considered an important contributor to the HF phenotype. However, there is limited electrophysiological data from the human heart. OBJECTIVE To study electrophysiological remodeling of transmural repolarization in the failing and nonfailing human hearts. METHODS AND RESULTS We optically mapped the action potential duration (APD) in the coronary-perfused scar-free posterior-lateral left ventricular free wall wedge preparations from failing (n=5) and nonfailing (n=5) human hearts. During slow pacing (S1S1=2000 ms), in the nonfailing hearts we observed significant transmural APD gradient: subepicardial, midmyocardial, and subendocardial APD80 were 383+/-21, 455+/-20, and 494+/-22 ms, respectively. In 60% of nonfailing hearts (3 of 5), we found midmyocardial islands of cells that presented a distinctly long APD (537+/-40 ms) and a steep local APD gradient (27+/-7 ms/mm) compared with the neighboring myocardium. HF resulted in prolongation of APD80: 477+/-22 ms, 495+/-29 ms, and 506+/-35 ms for the subepi-, mid-, and subendocardium, respectively, while reducing transmural APD80 difference from 111+/-13 to 29+/-6 ms (P<0.005) and presence of any prominent local APD gradient. In HF, immunostaining revealed a significant reduction of connexin43 expression on the subepicardium. CONCLUSIONS We present for the first time direct experimental evidence of a transmural APD gradient in the human heart. HF results in the heterogeneous prolongation of APD, which significantly reduces the transmural and local APD gradients.
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Affiliation(s)
- Alexey V Glukhov
- Department of Biomedical Engineering, Washington University, St Louis, MO 63130, USA
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Autonomic nervous system activity measured directly and QT interval variability in normal and pacing-induced tachycardia heart failure dogs. J Am Coll Cardiol 2009; 54:840-50. [PMID: 19695465 DOI: 10.1016/j.jacc.2009.06.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 05/28/2009] [Accepted: 06/17/2009] [Indexed: 11/21/2022]
Abstract
OBJECTIVES This study sought to find out more about the relationship between sympathetic and vagal nerve activity and the cardiac repolarization in a canine model of pacing-induced tachycardia congestive heart failure (CHF). BACKGROUND The QT variability index (QTVI), a noninvasive marker of temporal cardiac repolarization dispersion, is among the risk factors for sudden death during CHF. Among factors influencing this variable are the myocardial damage and the autonomic nervous system activity typical of dilated cardiomyopathy. METHODS We assessed autonomic nervous system activity recorded from an implanted data transmitter that monitored integrated left stellate-ganglion nervous activity, integrated vagus nerve activity, and electrocardiogram. We collected 36 segments recorded at baseline and 36 after induced CHF. We then arbitrarily identified recording segments as containing low or high sympathetic activity values, and we compared corrected QT intervals and the QTVI under a given sympathetic activity condition at baseline and after inducing CHF. RESULTS In the high sympathetic activity subgroup, both QT variables increased from baseline to CHF (corrected QT intervals, p < 0.01; QTVI, p < 0.05) whereas in the low sympathetic activity subgroup they remained unchanged. The baseline QTVI correlated inversely with integrated vagus nerve activity (r(2) = 0.16; beta = -0.47; p < 0.05) whereas, during CHF, the QTVI correlated directly with integrated left stellate-ganglion nervous activity (r(2) = 0.32; beta = 0.27, p < 0.01). CONCLUSIONS During CHF, sympathetic activation is associated with an increase in the QT interval and QTVI. Because these changes vary over time, they could result from myocardial structural damage and sympathetic activation combined. Conversely, under normal conditions, no relationship exists between sympathetic activation and the QT variables.
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Sipido KR, Tedgui A, Kristensen SD, Pasterkamp G, Schunkert H, Wehling M, Steg PG, Eisert W, Rademakers F, Casadei B, Fuster V, Cerbai E, Hasenfuss G, Fernandez-Aviles F, Garcia-Dorado D, Vidal M, Hallen M, Dambrauskaite V. Identifying needs and opportunities for advancing translational research in cardiovascular disease. Cardiovasc Res 2009; 83:425-35. [PMID: 19502281 DOI: 10.1093/cvr/cvp165] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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