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Ozdemir R, Tanır Y, Demir BB, Yılmaz S, Geçkalan Soysal D, Karadeniz C. The effect of long-term use of methylphenidate on cardiac autonomic functions and ventricular arrhythmogenesis: a prospective case-control study. Cardiol Young 2024; 34:32-36. [PMID: 37138525 DOI: 10.1017/s1047951123001038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
OBJECTIVE We aimed to assess cardiac autonomic balance with heart rate variability by using 24-hour Holter electrocardiography and also to assess susceptibility to ventricular arrhythmias by using microvolt T wave alternance in children with attention deficit hyperactivity disorder. METHOD This study was conducted with age- and gender-matched groups of 40 patients taking long-acting methylphenidate for more than a year and 55 healthy controls. Heart rate variability analysis for cardiac autonomic functions and microvolt T wave alternance measurements for susceptibility to ventricular arrhythmias were evaluated by 24-hour Holter electrocardiography. RESULTS The mean age 10.9 ± 2.7 years, mean duration of therapy 22.76 months, and mean methylphenidate doses were 37.64 mg/day. The study group had considerably higher rMSSD, higher HF, and a lower LF/HF ratio (respectively, p : 0.02, p : 0.001 and p : 0.01). While parasympathetic activity parameters were elevated, sympathetic activity parameters were low during the sleep period. Increase in the microvolt T wave alternance values of the study group was not found to be statistically significant (p > 0.05). CONCLUSION In children taking long-acting methylphenidate, the autonomic balance was shown to be in favour of the parasympathetic system. Determination of the vulnerability to life-threatening ventricular arrhythmias has been evaluated for the first time in children with attention deficit hyperactivity disorder. Accordingly, microvolt T-wave alternance values give the notion that drug use is safe.
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Affiliation(s)
- Rahmi Ozdemir
- Pediatric Cardiology, Kütahya Health Sciences University, Kutahya, Turkey
| | - Yaşar Tanır
- Child and Adolescent Psychiatry, Kütahya Health Sciences University, Kutahya, Turkey
| | | | - Seheryeli Yılmaz
- Child and Adolescent Psychiatry, Kütahya Health Sciences University, Kutahya, Turkey
| | | | - Cem Karadeniz
- Department of Pediatric Cardiology, School of Medicine, Katip Celebi University, Izmir, Turkey
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Wang M, Xu Y, Wang S, Zhao T, Cai H, Wang Y, Zou R, Wang C. Predictive value of electrocardiographic markers in children with dilated cardiomyopathy. Front Pediatr 2022; 10:917730. [PMID: 36081634 PMCID: PMC9445218 DOI: 10.3389/fped.2022.917730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Dilated cardiomyopathy (DCM) refers to a heterogeneous group of cardiomyopathies characterized by ventricular dilatation and myocardial systolic dysfunction, which can lead to serious consequences such as malign arrhythmia, sudden death, heart failure, and thromboembolism. With its economical, non-invasive, simple and reproducible advantages, electrocardiogram (ECG) has become an important indicator for assessing the prognosis of cardiovascular diseases. In recent years, more and more studies of electrocardiography on DCM have been carried out, but there is still a lack of a comprehensive summary of its prognostic value. This article reviews the prognostic value of electrocardiographic markers in children with DCM.
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Affiliation(s)
- Miao Wang
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yi Xu
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Shuo Wang
- Department of Neonatology, Xiangya Hospital, Central South University, Changsha, China
| | - Ting Zhao
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Hong Cai
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yuwen Wang
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Runmei Zou
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Cheng Wang
- Department of Pediatric Cardiovasology, Children's Medical Center, The Second Xiangya Hospital, Central South University, Changsha, China
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Hazim A, Belhamadia Y, Dubljevic S. A Simulation Study of the Role of Mechanical Stretch in Arrhythmogenesis during Cardiac Alternans. Biophys J 2020; 120:109-121. [PMID: 33248131 PMCID: PMC7820729 DOI: 10.1016/j.bpj.2020.11.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 11/03/2020] [Accepted: 11/13/2020] [Indexed: 12/20/2022] Open
Abstract
The deformation of the heart tissue due to the contraction can modulate the excitation, a phenomenon referred to as mechanoelectrical feedback (MEF), via stretch-activated channels. The effects of MEF on the electrophysiology at high pacing rates are shown to be proarrhythmic in general. However, more studies need to be done to elucidate the underlying mechanism. In this work, we investigate the effects of MEF on cardiac alternans, which is an alternation in the width of the action potential that typically occurs when the heart is paced at high rates, using a biophysically detailed electromechanical model of cardiac tissue. We observe that the transition from spatially concordant alternans to spatially discordant alternans, which is more arrhythmogenic than concordant alternans, may occur in the presence of MEF and when its strength is sufficiently large. We show that this transition is due to the increase of the dispersion of conduction velocity. In addition, our results also show that the MEF effects, depending on the stretch-activated channels’ conductances and reversal potentials, can result in blocking action potential propagation.
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Affiliation(s)
- Azzam Hazim
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Youssef Belhamadia
- Department of Mathematics and Statistics, American University of Sharjah, Sharjah, United Arab Emirates
| | - Stevan Dubljevic
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada.
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Marcantoni I, Sbrollini A, Agostinelli G, Surace FC, Colaneri M, Morettini M, Pozzi M, Burattini L. T-Wave Alternans in Nonpathological Preterm Infants. Ann Noninvasive Electrocardiol 2020; 25:e12745. [PMID: 31986237 PMCID: PMC7358874 DOI: 10.1111/anec.12745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/17/2019] [Accepted: 12/30/2019] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Sudden infant death syndrome is more frequent in preterm infants (PTI) than term infants and may be due to cardiac repolarization instability, which may manifest as T-wave alternans (TWA) on the electrocardiogram (ECG). Therefore, the aim of the present work was to analyze TWA in nonpathological PTI and to open an issue on its physiological interpretation. METHODS Clinical population consisted of ten nonpathological PTI (gestational age ranging from 29 3 7 to 34 2 7 weeks; birth weight ranging from 0.84 to 2.10 kg) from whom ECG recordings were obtained ("Preterm infant cardio-respiratory signals database" by Physionet). TWA was identified through the heart-rate adapting match filter method and characterized in terms of mean amplitude values (TWAA). TWA correlation with several other clinical and ECG features, among which gestational age-birth weight ratio, RR interval, heart-rate variability, and QT interval, was also performed. RESULTS TWA was variable among infants (TWAA = 26 ± 11 µV). Significant correlations were found between TWAA versus birth weight (ρ = -0.72, p = .02), TWAA versus gestational age-birth weight ratio (ρ = 0.76, p = .02) and TWAA versus heart-rate variability (ρ = -0.71, p = .02). CONCLUSIONS Our preliminary retrospective study suggests that nonpathological PTI show TWA of few tens of µV, the interpretation of which is still an open issue but could indicate a condition of cardiac risk possibly related to the low development status of the infant. Further investigations are needed to solve this issue.
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Affiliation(s)
- Ilaria Marcantoni
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Agnese Sbrollini
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Gloria Agostinelli
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Francesca Chiara Surace
- Department of Paediatric and Congenital Cardiac Surgery and Cardiology, Ospedali Riuniti, Ancona, Italy
| | - Massimo Colaneri
- Department of Paediatric and Congenital Cardiac Surgery and Cardiology, Ospedali Riuniti, Ancona, Italy
| | - Micaela Morettini
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
| | - Marco Pozzi
- Department of Paediatric and Congenital Cardiac Surgery and Cardiology, Ospedali Riuniti, Ancona, Italy
| | - Laura Burattini
- Department of Information Engineering, Università Politecnica delle Marche, Ancona, Italy
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Hazim A, Belhamadia Y, Dubljevic S. Mechanical perturbation control of cardiac alternans. Phys Rev E 2018; 97:052407. [PMID: 29906969 DOI: 10.1103/physreve.97.052407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Indexed: 12/27/2022]
Abstract
Cardiac alternans is a disturbance in heart rhythm that is linked to the onset of lethal cardiac arrhythmias. Mechanical perturbation control has been recently used to suppress alternans in cardiac tissue of relevant size. In this control strategy, cardiac tissue mechanics are perturbed via active tension generated by the heart's electrical activity, which alters the tissue's electric wave profile through mechanoelectric coupling. We analyze the effects of mechanical perturbation on the dynamics of a map model that couples the membrane voltage and active tension systems at the cellular level. Therefore, a two-dimensional iterative map of the heart beat-to-beat dynamics is introduced, and a stability analysis of the system of coupled maps is performed in the presence of a mechanical perturbation algorithm. To this end, a bidirectional coupling between the membrane voltage and active tension systems in a single cardiac cell is provided, and a discrete form of the proposed control algorithm, that can be incorporated in the coupled maps, is derived. In addition, a realistic electromechanical model of cardiac tissue is employed to explore the feasibility of suppressing alternans at cellular and tissue levels. Electrical activity is represented in two detailed ionic models, the Luo-Rudy 1 and the Fox models, while two active contractile tension models, namely a smooth variant of the Nash-Panfilov model and the Niederer-Hunter-Smith model, are used to represent mechanical activity in the heart. The Mooney-Rivlin passive elasticity model is employed to describe passive mechanical behavior of the myocardium.
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Affiliation(s)
- Azzam Hazim
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2V2
| | - Youssef Belhamadia
- Department of Mathematics and Statistics, American University of Sharjah, Sharjah, United Arab Emirates
| | - Stevan Dubljevic
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2V4
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Hallioglu O, Keceli M, Bozlu G, Delibas A, Karpuz D, Selvi H. Evaluation of T-wave alternans in pediatric patients with chronic renal failure. J Electrocardiol 2018; 51:622-627. [PMID: 29997001 DOI: 10.1016/j.jelectrocard.2018.04.013] [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: 12/15/2017] [Revised: 03/10/2018] [Accepted: 04/18/2018] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Microvolt T-wave alternans (TWA) is known to be useful in prediction of ischemia and sudden death in high-risk populations and there are no studies in children with chronic renal failure (CRF). Cardiac problems seem to be responsible for an important part of death in children and young adults with CRF. The aim of this study is to evaluate Holter microvolts TWA measurements in children with CRF comparing to the control group. METHODS This prospective study included 40 patients with CRF and 48 healthy controls. The history, echocardiography and microvolt TWA values based on 24-hour ECG recordings of the patients were evaluated. Analysis of microvolt TWA was considered on the basis of three leads (V5, V1 and AVF). RESULTS Compared with the controls, the mean systolic and diastolic blood pressure values and average heart rates were significantly higher in the children with CRF (p = 0.001 and p = 0.026, respectively). Also, the values of left ventricular internal dimensions at end diastole and end-diastolic volume were significantly higher in CRF group (p = 0.01 and p = 0.049, respectively) and couplet ventricular extrasystole was detected in 2 patients with CRF. Consequently, all TWA values in three leads were increased in CRF group than the control group but the only increase in V5 lead was statistically significant (p = 0.028). CONCLUSIONS This study has demonstrated that microvolt TWA values increased in pediatric patients with CRF. TWA might be used for early risk assessment in pediatric patients with CRF in the future.
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Affiliation(s)
- Olgu Hallioglu
- Department of Pediatrics, University of Mersin Faculty of Medicine, Mersin, Turkey; Division of Pediatric Cardiology, University of Mersin Faculty of Medicine, Mersin, Turkey.
| | - Meryem Keceli
- Department of Pediatrics, University of Mersin Faculty of Medicine, Mersin, Turkey
| | - Gulcin Bozlu
- Department of Pediatrics, University of Mersin Faculty of Medicine, Mersin, Turkey
| | - Ali Delibas
- Department of Pediatrics, University of Mersin Faculty of Medicine, Mersin, Turkey; Division of Pediatric Nephrology, University of Mersin Faculty of Medicine, Mersin, Turkey
| | - Derya Karpuz
- Department of Pediatrics, University of Mersin Faculty of Medicine, Mersin, Turkey; Division of Pediatric Cardiology, University of Mersin Faculty of Medicine, Mersin, Turkey
| | - Hüseyin Selvi
- Department of Medical Education, University of Mersin Faculty of Medicine, Mersin, Turkey
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Abstract
Objective: To determine the values of microvolt T-wave alternans (MTWA) in children and adolescents with Eisenmenger syndrome (ES) and controls. Methods: Thirteen were included in the study. After analyzing the 24-h ECG recordings, MTWA was considered using three leads (V5, V1, and aVF). Right heart catheterization and 6-minute walk test (6-MWD) were applied to the patients and pro-brain natriuretic peptide levels were assessed; echocardiographic parameters were obtained from both the groups and the results were compared. Results: The MTWA value in lead V5 was 81.08±10.73 µV in the patient group (63.50±18.78 µV in the control group), in lead V1 was 75.00±16.86 µV (73.94±16.77 µV in the control group), and in lead aVF was 73.77±17.81 µV (72.61±16.21 µV in the control group). Comparison of MTWA values between patients and controls revealed that only lead V5 values were statistically different in the ES group. The 6-MWD scores significantly correlated with lead V5. Right atrial volume and right ventricular fractional area change were significantly correlated with lead V1. The Tei index was significantly correlated with lead aVF. Conclusion: The MTWA lead V5 value was significantly higher in children with ES than in controls and was also correlated with decreased exercise tolerance.
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Quantitative T-wave alternans analysis for sudden cardiac death risk assessment and guiding therapy: answered and unanswered questions. J Electrocardiol 2016; 49:429-38. [DOI: 10.1016/j.jelectrocard.2016.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Indexed: 11/23/2022]
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Doksöz Ö, Meşe T, Karaarslan U, Ceylan G, Demirpençe S, Tavlı V, Ünal N. Assessment of Microvolt T Wave Alternans in Children with Repaired Tetralogy of Fallot during 24-Hour Holter Electrocardiography. Ann Noninvasive Electrocardiol 2015; 21:369-75. [PMID: 26524222 DOI: 10.1111/anec.12315] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 08/13/2015] [Accepted: 08/25/2015] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND We aimed to examine microvolt T wave alternans (MTWA) in 24-hour Holter electrocardiography (ECG) of children with repaired tetralogy of Fallot (TOF) to assess associations of MTWA with ventricular arrhythmias, ECG parameters, and echocardiographic findings. METHODS Holter ECG records and archive files of 56 repaired TOF patients (62.5% male) who were analyzed retrospectively. Subjects' ECG parameters and MTWA values were compared with age-sex-matched control group. T wave changes were analyzed by time-domain-modified moving average method from the three channels of 24-hour Holter ECG. RESULTS Mean age was 123.4 ± 48.3 months. Median MTWA value was 55.5 μV in the control group, whereas 95.5 μV in patients group (P < 0.001). A significant weak positive correlation was found between the presence of ventricular extrasystoles and tricuspid regurgitation. There was no correlation between ECG parameters, echocardiographic findings, and MTWA. CONCLUSIONS MTWA was increased in children with repaired TOF as reported before. To our knowledge, this is the first study analyzing MTWA with 24-hour Holter ECG in repaired TOF patients.
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Affiliation(s)
- Önder Doksöz
- Department of Pediatric Cardiology, Izmir Dr. Behçet Uz Children's Hospital, Izmir, Turkey
| | - Timur Meşe
- Department of Pediatric Cardiology, Izmir Dr. Behçet Uz Children's Hospital, Izmir, Turkey
| | - Utku Karaarslan
- Department of Pediatric Intensive Care Unit, Faculty of Medicine, Dokuz Eylül University, Izmir, Turkey
| | - Gökhan Ceylan
- Department of Pediatric Intensive Care Unit, Izmir Dr. Behçet Uz Children's Hospital, Izmir, Turkey
| | - Savaş Demirpençe
- Department of Pediatric Cardiology, Faculty of Medicine, Şifa University, Izmir, Turkey
| | - Vedide Tavlı
- Department of Pediatric Cardiology, Faculty of Medicine, Şifa University, Izmir, Turkey
| | - Nurettin Ünal
- Department of Pediatric Cardiology, Faculty of Medicine, Dokuz Eylül University, Izmir, Turkey
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Hazim A, Belhamadia Y, Dubljevic S. Control of cardiac alternans in an electromechanical model of cardiac tissue. Comput Biol Med 2015; 63:108-17. [PMID: 26069933 DOI: 10.1016/j.compbiomed.2015.05.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 11/26/2022]
Abstract
Electrical alternations in cardiac action potential duration have been shown to be a precursor to arrhythmias and sudden cardiac death. Through the mechanism of excitation-contraction coupling, the presence of electrical alternans induces alternations in the heart muscle contractile activity. Also, contraction of cardiac tissue affects the process of cardiac electric wave propagation through the mechanism of the so-called mechanoelectrical feedback. Electrical excitation and contraction of cardiac tissue can be linked by an electromechanical model such as the Nash-Panfilov model. In this work, we explore the feasibility of suppressing cardiac alternans in the Nash-Panfilov model which is employed for small and large deformations. Several electrical pacing and mechanical perturbation feedback strategies are considered to demonstrate successful suppression of alternans on a one-dimensional cable. This is the first attempt to combine electrophysiologically relevant cardiac models of electrical wave propagation and contractility of cardiac tissue in a synergistic effort to suppress cardiac alternans. Numerical examples are provided to illustrate the feasibility and the effects of the proposed algorithms to suppress cardiac alternans.
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Affiliation(s)
- Azzam Hazim
- Department of Biomedical Engineering, University of Alberta, Edmonton, AB Canada T6G 2V2
| | - Youssef Belhamadia
- Department of Biomedical Engineering, Department of Mathematics and Campus Saint-Jean, University of Alberta, AB Canada T6C 4G9
| | - Stevan Dubljevic
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB Canada T6G 2V4.
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Verrier RL, Malik M. Quantitative T-wave alternans analysis for guiding medical therapy: an underexploited opportunity. Trends Cardiovasc Med 2014; 25:201-13. [PMID: 25541329 DOI: 10.1016/j.tcm.2014.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/09/2014] [Accepted: 10/09/2014] [Indexed: 11/18/2022]
Abstract
Reducing the toll of sudden cardiac death (SCD) remains a major challenge in cardiology, as it is the leading cause of adult mortality in the industrially developed world, claiming 310,000 lives annually in the United States alone. The main contemporary noninvasive index of cardiovascular risk, left ventricular ejection fraction (LVEF), has not proved adequately reliable, as the majority of individuals who die suddenly have relatively preserved cardiac mechanical function. Monitoring of T-wave alternans (TWA), a beat-to-beat fluctuation in ST-segment or T-wave morphology, is an attractive approach to risk stratification on both scientific and clinical grounds, as this ECG phenomenon has been shown using the FDA-cleared Spectral and Modified Moving Average methods to assess risk for cardiovascular mortality including SCD in studies enrolling >12,000 individuals with depressed or preserved LVEF. The evidence supporting TWA as a therapeutic target is reviewed.
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Affiliation(s)
- Richard L Verrier
- Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA.
| | - Marek Malik
- St. Paul׳s Cardiac Electrophysiology, University of London, and Imperial College, London, United Kingdom
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Yapari F, Deshpande D, Belhamadia Y, Dubljevic S. Control of cardiac alternans by mechanical and electrical feedback. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:012706. [PMID: 25122334 DOI: 10.1103/physreve.90.012706] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Indexed: 06/03/2023]
Abstract
A persistent alternation in the cardiac action potential duration has been linked to the onset of ventricular arrhythmia, which may lead to sudden cardiac death. A coupling between these cardiac alternans and the intracellular calcium dynamics has also been identified in previous studies. In this paper, the system of PDEs describing the small amplitude of alternans and the alternation of peak intracellular Ca(2+) are stabilized by optimal boundary and spatially distributed actuation. A simulation study demonstrating the successful annihilation of both alternans on a one-dimensional cable of cardiac cells by utilizing the full-state feedback controller is presented. Complimentary to these studies, a three variable Nash-Panfilov model is used to investigate alternans annihilation via mechanical (or stretch) perturbations. The coupled model includes the active stress which defines the mechanical properties of the tissue and is utilized in the feedback algorithm as an independent input from the pacing based controller realization in alternans annihilation. Simulation studies of both control methods demonstrate that the proposed methods can successfully annihilate alternans in cables that are significantly longer than 1 cm, thus overcoming the limitations of earlier control efforts.
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Affiliation(s)
- Felicia Yapari
- Deparment of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 Canada
| | - Dipen Deshpande
- Deparment of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 Canada
| | - Youssef Belhamadia
- Campus Saint-Jean and Department of Mathematics, University of Alberta, Edmonton, Alberta, T6C 4G9 Canada
| | - Stevan Dubljevic
- Deparment of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 2V4 Canada
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Burattini L, Man S, Burattini R, Swenne CA. Comparison of standard versus orthogonal ECG leads for T-wave alternans identification. Ann Noninvasive Electrocardiol 2012; 17:130-40. [PMID: 22537331 DOI: 10.1111/j.1542-474x.2012.00490.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
T-wave alternans (TWA), an electrophysiologic phenomenon associated with ventricular arrhythmias, is usually detected from selected ECG leads. TWA amplitude measured in the 12-standard and the 3-orthogonal (vectorcardiographic) leads were compared here to identify which lead system yields a more adequate detection of TWA as a noninvasive marker for cardiac vulnerability to ventricular arrhythmias. Our adaptive match filter (AMF) was applied to exercise ECG tracings from 58 patients with an implanted cardiac defibrillator, 29 of which had ventricular tachycardia or fibrillation during follow-up (cases), while the remaining 29 were used as controls. Two kinds of TWA indexes were considered, the single-lead indexes, defined as the mean TWA amplitude over each lead (MTWAA), and lead-system indexes, defined as the mean and the maximum MTWAA values over the standard leads and over the orthogonal leads. Significantly (P < 0.05) higher TWA in the cases versus controls was identified only occasionally by the single-lead indexes (odds ratio: 1.0-9.9, sensitivity: 24-76%, specificity: 76-86%), and consistently by the lead-system indexes (odds ratio: 4.5-8.3, sensitivity: 57-72%, specificity: 76%). The latter indexes also showed a significant correlation (0.65-0.83) between standard and orthogonal leads. Hence, when using the AMF, TWA should be detected in all leads of a system to compute the lead-system indexes, which provide a more reliable TWA identification than single-lead indexes, and a better discrimination of patients at increased risk of cardiac instability. The standard and the orthogonal leads can be considered equivalent for TWA identification, so that TWA analysis can be limited to one-lead system.
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Affiliation(s)
- Laura Burattini
- Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy.
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Burattini L, Bini S, Burattini R. Automatic microvolt T-wave alternans identification in relation to ECG interferences surviving preprocessing. Med Eng Phys 2011; 33:17-30. [PMID: 20920875 DOI: 10.1016/j.medengphy.2010.08.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 08/10/2010] [Accepted: 08/25/2010] [Indexed: 10/19/2022]
Abstract
The aim was to investigate the effect of interferences surviving preprocessing (residual noise, baseline wanderings, respiration modulation, replaced beats, missed beats and T-waves misalignment) on automatic identification of T-wave alternans (TWA), an ECG index of risk for sudden cardiac death. The procedures denominated fast-Fourier-transform spectral method (FFTSM), complex-demodulation method (CDM), modified-moving-average method (MMAM), Laplacian-likelihood-ratio method (LLRM), and adaptive-match-filter method (AMFM) were applied to interferences-corrupted synthetic ECG tracings and Holter ECG recordings from control-healthy subjects (CH-group; n=25) and acute-myocardial-infarction patients (AMI group; n=25). The presence of interferences in simulated data caused detection of false-positive TWA by all techniques but the FFTSM and AMFM. Clinical applications evidenced a discrepancy in that the FFTSM and LLRM detected no more than one TWA case in each population, whereas the CDM, MMAM, and AMFM detected TWA in all CH-subjects and AMI-patients, with significantly lower TWA amplitude in the former group. Because the AMFM is not prone to false-positive TWA detections, the latter finding suggests TWA as a phenomenon having continuously changing amplitude from physiological to pathological conditions. Only occasional detection of TWA by the FFTSM and LLRM in clinics can be ascribed to their limited ability in identifying TWA in the presence of interferences surviving preprocessing.
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Affiliation(s)
- Laura Burattini
- Department of Biomedical, Electronics and Telecommunication Engineering, Polytechnic University of Marche, Via Brecce Bianche, 60131 Ancona, Italy
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