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Sammani A, van de Leur RR, Henkens MTHM, Meine M, Loh P, Hassink RJ, Oberski DL, Heymans SRB, Doevendans PA, Asselbergs FW, te Riele ASJM, van Es R. Life-threatening ventricular arrhythmia prediction in patients with dilated cardiomyopathy using explainable electrocardiogram-based deep neural networks. Europace 2022; 24:1645-1654. [PMID: 35762524 PMCID: PMC9559909 DOI: 10.1093/europace/euac054] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 04/10/2022] [Indexed: 11/17/2022] Open
Abstract
AIMS While electrocardiogram (ECG) characteristics have been associated with life-threatening ventricular arrhythmias (LTVA) in dilated cardiomyopathy (DCM), they typically rely on human-derived parameters. Deep neural networks (DNNs) can discover complex ECG patterns, but the interpretation is hampered by their 'black-box' characteristics. We aimed to detect DCM patients at risk of LTVA using an inherently explainable DNN. METHODS AND RESULTS In this two-phase study, we first developed a variational autoencoder DNN on more than 1 million 12-lead median beat ECGs, compressing the ECG into 21 different factors (F): FactorECG. Next, we used two cohorts with a combined total of 695 DCM patients and entered these factors in a Cox regression for the composite LTVA outcome, which was defined as sudden cardiac arrest, spontaneous sustained ventricular tachycardia, or implantable cardioverter-defibrillator treated ventricular arrhythmia. Most patients were male (n = 442, 64%) with a median age of 54 years [interquartile range (IQR) 44-62], and median left ventricular ejection fraction of 30% (IQR 23-39). A total of 115 patients (16.5%) reached the study outcome. Factors F8 (prolonged PR-interval and P-wave duration, P < 0.005), F15 (reduced P-wave height, P = 0.04), F25 (increased right bundle branch delay, P = 0.02), F27 (P-wave axis P < 0.005), and F32 (reduced QRS-T voltages P = 0.03) were significantly associated with LTVA. CONCLUSION Inherently explainable DNNs can detect patients at risk of LTVA which is mainly driven by P-wave abnormalities.
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MESH Headings
- Arrhythmias, Cardiac/complications
- Arrhythmias, Cardiac/diagnosis
- Arrhythmias, Cardiac/therapy
- Cardiomyopathy, Dilated/complications
- Cardiomyopathy, Dilated/diagnosis
- Death, Sudden, Cardiac/etiology
- Death, Sudden, Cardiac/prevention & control
- Defibrillators, Implantable
- Electrocardiography/methods
- Female
- Humans
- Male
- Middle Aged
- Neural Networks, Computer
- Risk Factors
- Stroke Volume
- Ventricular Function, Left/physiology
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Affiliation(s)
- Arjan Sammani
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Rutger R van de Leur
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Michiel T H M Henkens
- Department of Cardiology, CARIM, Maastricht University Medical Centre, Maastricht, The Netherlands
- Netherlands Heart Institute (NLHI), Utrecht, The Netherlands
| | - Mathias Meine
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Peter Loh
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Rutger J Hassink
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Daniel L Oberski
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- Department of Methodology and Statistics, Faculty of Social Sciences, Utrecht University and University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Stephane R B Heymans
- Department of Cardiology, CARIM, Maastricht University Medical Centre, Maastricht, The Netherlands
- Netherlands Heart Institute (NLHI), Utrecht, The Netherlands
- Department of Cardiovascular Research, University of Leuven, Leuven, Belgium
| | - Pieter A Doevendans
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- Netherlands Heart Institute (NLHI), Utrecht, The Netherlands
- Central Military Hospital, Utrecht, The Netherlands
| | - Folkert W Asselbergs
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- Institute of Cardiovascular Science and Institute of Health Informatics, Faculty of Population Health Sciences, University College London, London, UK
| | - Anneline S J M te Riele
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - René van Es
- Department of Cardiology, University Medical Centre Utrecht, University of Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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2
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Engstrom N, Dobson GP, Ng K, Lander K, Win K, Gupta A, Letson HL. Validation of CalECG software for primary prevention heart failure patients: Reducing inter-observer measurement variability. J Electrocardiol 2022; 74:128-133. [PMID: 36191576 DOI: 10.1016/j.jelectrocard.2022.09.011] [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: 06/26/2022] [Revised: 08/09/2022] [Accepted: 09/19/2022] [Indexed: 12/13/2022]
Abstract
BACKGROUND In primary prevention heart failure patients the 12‑lead electrocardiogram (ECG) may be useful for the prediction of ventricular arrhythmias. However, inter-observer measurement variability first needs to be identified and any software used, validated. OBJECTIVE To compare manual ECG measures with CalECG software and to assess the reliability of visual recognition of fragmented QRS (fQRS) by advanced cardiology trainees. METHODS 30 pre-implant ECGs were assessed on patients who met guidelines for primary prevention Implantable Cardiac Defibrillator. Parameters included RR, PR, QT, QRS duration, axis location, fQRS and T wave peak to T wave end (TpTe). ECGs were analyzed by members of the cardiology department with different levels of experience, and compared to CalECG software. Interobserver agreement was assessed using Fleiss' Kappa (κ) and intraclass correlation coefficients (ICC). Pearson correlation coefficient (r) was used to compare human and software measures. RESULTS Strong/very strong correlation was recorded across manual ECG measures (ICC = 0.749-0.979, p ≤ 0.0001) with moderate/strong correlation for TpTe (ICC = 0.547-0.765, p ≤ 0.001). Advanced cardiology trainees demonstrated substantial agreement on ECG interpretation (κ = 0.788, p ≤ 0.0001), however, reliability of fQRS assessment was only moderate for identification (κ = 0.5, p ≤ 0.0001) and fair for location (κ = 0.295, p = 0.001). CalECG software showed strong/very strong correlation with manual measurement for standard measures (r = 0.756-0.977, p ≤ 0.001). Concordance between human and software TpTe measurements varied between leads, with V5 showing a non-significant weak correlation (r = 0.197). CONCLUSION CalECG software showed strong/very strong correlation with standard manual measures which affirms its use in ECG analysis. Advanced cardiology trainees showed greater variability in the identification and location of fQRS.
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Affiliation(s)
- Nathan Engstrom
- College of Medicine & Dentistry, Heart and Trauma Research Laboratory, James Cook University, 1 James Cook Drive, Townsville, QLD 4811, Australia; Cardiac Investigations, Townsville University Hospital, 100 Angus Smith Drive, Douglas, QLD 4814, Australia.
| | - Geoffrey P Dobson
- College of Medicine & Dentistry, Heart and Trauma Research Laboratory, James Cook University, 1 James Cook Drive, Townsville, QLD 4811, Australia.
| | - Kevin Ng
- Cardiology Clinic, Cairns Hospital, 165 Esplanade, Cairns, QLD 4870, Australia.
| | - Krystle Lander
- Cardiology Department, Townsville University Hospital, 100 Angus Smith Drive, Douglas, QLD 4814, Australia.
| | - Kyi Win
- Cardiology Department, Townsville University Hospital, 100 Angus Smith Drive, Douglas, QLD 4814, Australia.
| | - Anudeep Gupta
- Cardiology Department, Townsville University Hospital, 100 Angus Smith Drive, Douglas, QLD 4814, Australia.
| | - Hayley L Letson
- College of Medicine & Dentistry, Heart and Trauma Research Laboratory, James Cook University, 1 James Cook Drive, Townsville, QLD 4811, Australia.
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3
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A machine learning algorithm for electrocardiographic fQRS quantification validated on multi-center data. Sci Rep 2022; 12:6783. [PMID: 35474073 PMCID: PMC9043208 DOI: 10.1038/s41598-022-10452-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 04/07/2022] [Indexed: 12/02/2022] Open
Abstract
Fragmented QRS (fQRS) is an electrocardiographic (ECG) marker of myocardial conduction abnormality, characterized by additional notches in the QRS complex. The presence of fQRS has been associated with an increased risk of all-cause mortality and arrhythmia in patients with cardiovascular disease. However, current binary visual analysis is prone to intra- and inter-observer variability and different definitions are problematic in clinical practice. Therefore, objective quantification of fQRS is needed and could further improve risk stratification of these patients. We present an automated method for fQRS detection and quantification. First, a novel robust QRS complex segmentation strategy is proposed, which combines multi-lead information and excludes abnormal heartbeats automatically. Afterwards extracted features, based on variational mode decomposition (VMD), phase-rectified signal averaging (PRSA) and the number of baseline-crossings of the ECG, were used to train a machine learning classifier (Support Vector Machine) to discriminate fragmented from non-fragmented ECG-traces using multi-center data and combining different fQRS criteria used in clinical settings. The best model was trained on the combination of two independent previously annotated datasets and, compared to these visual fQRS annotations, achieved Kappa scores of 0.68 and 0.44, respectively. We also show that the algorithm might be used in both regular sinus rhythm and irregular beats during atrial fibrillation. These results demonstrate that the proposed approach could be relevant for clinical practice by objectively assessing and quantifying fQRS. The study sets the path for further clinical application of the developed automated fQRS algorithm.
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4
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Vandenberk B, Engelen MM, Van De Sijpe G, Vermeulen J, Janssens S, Vanassche T, Verhamme P, De Munter P, Lorent N, Willems R. Repolarization abnormalities on admission predict 1-year outcome in COVID-19 patients. IJC HEART & VASCULATURE 2021; 37:100912. [PMID: 34751251 PMCID: PMC8565995 DOI: 10.1016/j.ijcha.2021.100912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 10/29/2021] [Indexed: 12/26/2022]
Abstract
Background ECG abnormalities in COVID-19 have been widely reported, however data after discharge is limited. The aim was to describe ECG abnormalities on admission and following recovery of COVID-19, and their associated mortality. Methods All patients hospitalized in a tertiary care hospital between March 7th and July 1st 2020 with COVID-19 were included in a retrospective registry. The first ECG on admission was collected, together with an ECG after hospital discharge in the absence of acute pathology. Automated measures and clinical ECG interpretations were collected. Multivariate Cox regression analysis was performed to predict 1-year all-cause mortality. Results In total 420 patients were included, of which 83 patients (19.8%) died during the 1-year follow-up period. Repolarization abnormalities were present in 189 patients (45.0%). The extent of repolarization abnormalities was an independent predictor of 1-year all-cause mortality (HR per region 1.30, 95%CI 1.04–1.64) together with age (/year HR 1.06, 95%CI 1.04–1.08), heart rate (/bpm HR 1.02, 95%CI 1.01–1.03), neurological disorders (HR 2.41, 95%CI 1.47–3.93), active cancer (HR 2.75, 95%CI 1.57–4.82), CRP (per 10 mg/L HR 1.05, 95%CI 1.02–1.08) and eGFR (per 10 mg/L HR 0.90, 95%CI 0.83–0.98). In 245 patients (68.1%) an ECG post discharge was available. New repolarization abnormalities were more frequent in patients who died after discharge (4.7% versus 41.7%, p < 0.001) and 8 (3.3%) had new ventricular conduction defects, none of whom died during follow-up. Conclusions The presence and extent of repolarization abnormalities predicted outcome in patients with COVID-19. New repolarization abnormalities after discharge were associated with post-discharge mortality.
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Affiliation(s)
- Bert Vandenberk
- Department of Cardiovascular Sciences, KU Leuven, Belgium.,Libin Cardiovascular Institute, University of Calgary, Canada.,Cardiology, University Hospitals Leuven, Belgium
| | - Matthias M Engelen
- Department of Cardiovascular Sciences, KU Leuven, Belgium.,Cardiology, University Hospitals Leuven, Belgium
| | - Greet Van De Sijpe
- Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Belgium
| | | | - Stefan Janssens
- Department of Cardiovascular Sciences, KU Leuven, Belgium.,Cardiology, University Hospitals Leuven, Belgium
| | - Thomas Vanassche
- Department of Cardiovascular Sciences, KU Leuven, Belgium.,Cardiology, University Hospitals Leuven, Belgium
| | - Peter Verhamme
- Department of Cardiovascular Sciences, KU Leuven, Belgium.,Cardiology, University Hospitals Leuven, Belgium
| | - Paul De Munter
- General Internal Medicine, University Hospitals Leuven, Belgium.,Department of Microbiology, Immunology and Transplantation, KU Leuven, Belgium
| | - Natalie Lorent
- Respiratory Diseases, University Hospitals Leuven, Belgium
| | - Rik Willems
- Department of Cardiovascular Sciences, KU Leuven, Belgium.,Cardiology, University Hospitals Leuven, Belgium
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5
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Miller JM, Das MK. Peering yet a little more behind the veil: Further insights from the ECG. Heart Rhythm 2021; 19:195-196. [PMID: 34757190 DOI: 10.1016/j.hrthm.2021.10.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 10/22/2021] [Indexed: 11/26/2022]
Affiliation(s)
- John M Miller
- Indiana University School of Medicine, Indianapolis, Indiana.
| | - Mithilesh K Das
- Indiana University School of Medicine, Indianapolis, Indiana
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6
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Kareem M, Lei N, Ali A, Ciaccio EJ, Acharya UR, Faust O. A review of patient-led data acquisition for atrial fibrillation detection to prevent stroke. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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ÇEVİK BŞ, ARICI Ş, ERGENÇ Z, KEPENEKLİ E, GÜNAL Ö, YAKUT N. How safe are children with COVID-19 from cardiac risks? Pediatric risk assesment; insights from echocardiography and electrocardiography. Turk J Med Sci 2021; 51:981-990. [PMID: 33517608 PMCID: PMC8283426 DOI: 10.3906/sag-2010-240] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/30/2021] [Indexed: 12/15/2022] Open
Abstract
Background/aim Approximately 40 million individuals worldwide have been infected with SARS-CoV-2, the virus responsible for the novel coronavirus disease-2019 (COVID-19). Despite the current literature about the cardiac effects of COVID-19 in children, more information is required. We aimed to determine both cardiovascular and arrhythmia assessment via electrocardiographic and echocardiographic parameters. Materials and methods We evaluated seventy children who were hospitalized with COVID-19 infections and seventy children as normal control group through laboratory findings, electrocardiography (ECG), and transthoracic echocardiography (TTE). Results We observed significantly increased levels of Tp-Te, Tp-Te/QT, and Tp-Te/QTc compared with the control group. Twenty-five of 70 (35.7%) patients had fragmented QRS (fQRS) without increased troponin levels. On the other hand, none of the patients had pathologic corrected QT(QTc) prolongation during the illness or its treatment. On TTE, 20 patients had mild mitral insufficiency, among whom only five had systolic dysfunction (ejection fraction < 55%). There was no significant difference between the patient and control groups, except for isovolumic relaxation time (IVRT) in terms of mean systolic and diastolic function parameters. IVRT of COVID patients was significantly lower than that of control group. Conclusion Despite all the adult studies, the effects of COVID‐19 on myocardial function are not well established in children. The thought that children are less affected by the illness may be a misconception.
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Affiliation(s)
- Berna Şaylan ÇEVİK
- Department of Pediatric Cardiology, Marmara University School of Medicine, İstanbulTurkey
| | - Şule ARICI
- Department of Pediatric Cardiology, Marmara University School of Medicine, İstanbulTurkey
| | - Zeynep ERGENÇ
- Department of Pediatric Infection Disease, Marmara University School of Medicine, İstanbulTurkey
| | - Eda KEPENEKLİ
- Department of Pediatric Infection Disease, Marmara University School of Medicine, İstanbulTurkey
| | - Özge GÜNAL
- Department of Pediatrics, Marmara University School of Medicine, İstanbulTurkey
| | - Nurhayat YAKUT
- Department of Pediatric Infection Disease, Marmara University School of Medicine, İstanbulTurkey
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8
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Pranata R, Yonas E, Vania R, Tondas AE, Yuniadi Y. Fragmented QRS is associated with intraventricular dyssynchrony and independently predicts nonresponse to cardiac resynchronization therapy—Systematic review and meta‐analysis. Ann Noninvasive Electrocardiol 2020; 25:e12750. [PMID: 32187770 PMCID: PMC7358826 DOI: 10.1111/anec.12750] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 11/26/2019] [Accepted: 01/08/2020] [Indexed: 11/30/2022] Open
Abstract
Background Fragmented QRS (fQRS) is postulated to be associated with ventricular dyssynchrony and might be able to predict a nonresponse to cardiac resynchronization therapy (CRT) implantation. In this systematic review and meta‐analysis, we aim to assess whether fQRS can be a marker of intraventricular dyssynchronies in patients with ischemic and nonischemic cardiomyopathy and whether it is an independent predictor of nonresponse in patients receiving CRT. Methods We performed a comprehensive search on topics that assesses fQRS and its association with intraventricular dyssynchrony and nonresponse to CRT up until September 2019. Results Fragmented QRS is associated with intraventricular dyssynchrony (OR 10.34 [3.39, 31.54], p < .001; I2: 80% with sensitivity 76.8%, specificity 77%, LR+ 3.3, and LR− 0.3). Subgroup analysis showed that fQRS is associated with intraventricular dyssynchrony in patients with narrow QRS complex (OR 20.92 [12.24, 35.73], p < .001; I2: 0%) and nonischemic cardiomyopathy (OR of 19.97 [12.12, 32.92], p < .001; I2: 0%). Fragmented QRS was also associated with a higher time‐to‐peak myocardial sustained systolic (Ts‐SD) (OR 15.19 [12.58, 17.80], p < .001; I2: 0% and positive Yu index (OR 15.61 [9.07, 26.86], p < .001; I2: 0%). Fragmented QRS has a pooled adjusted OR of OR of 1.70 [1.35, 2.14], p < .001; I2: 62% for association with a nonresponse to CRT. QRS duration is found to be higher in nonresponders group mean difference −8.54 [−13.38, −3.70], p < .001; I2: 70%. Conclusion Fragmented QRS is associated with intraventricular dyssynchrony and is independently associated with nonresponse to cardiac resynchronization therapy.
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Affiliation(s)
- Raymond Pranata
- Faculty of Medicine Universitas Pelita Harapan Tangerang Indonesia
| | - Emir Yonas
- Faculty of Medicine Universitas YARSI Jakarta Indonesia
| | - Rachel Vania
- Faculty of Medicine Universitas Pelita Harapan Tangerang Indonesia
| | - Alexander Edo Tondas
- Department of Cardiology and Vascular Medicine Faculty of Medicine Universitas Sriwijaya Dr. Mohammad Hoesin General Hospital Palembang Indonesia
| | - Yoga Yuniadi
- Department of Cardiology and Vascular Medicine Faculty of Medicine Universitas Indonesia National Cardiovascular Center Harapan Kita Jakarta Indonesia
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9
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Supreeth RN, Francis J. Fragmented QRS - Its significance. Indian Pacing Electrophysiol J 2019; 20:27-32. [PMID: 31843558 PMCID: PMC6994396 DOI: 10.1016/j.ipej.2019.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 12/11/2019] [Indexed: 12/16/2022] Open
Abstract
Fragment QRS (fQRS) complex is a myocardial conduction abnormality that indicates myocardial scar. It is defined as additional notches in the QRS complex. Though initially fQRS was defined in the setting of normal QRS duration (<120 m s), later it has been expanded to include conditions with wide QRS complexes as in bundle branch block, ventricular ectopy and paced rhythm, when more than 2 notches are present. It is an important, yet often overlooked marker of mortality and arrhythmic events in many cardiac diseases. The significance of fQRS lies in the fact that it just requires a surface ECG for its recording and the value of information about the condition of the heart it dispenses based on the clinical setting. We review the role of fQRS in predicting adverse cardiac events in various conditions.
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Affiliation(s)
- R N Supreeth
- Baby Memorial Hospital, Kozhikode, Kerala, India
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10
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Goovaerts G, Padhy S, Vandenberk B, Varon C, Willems R, Van Huffel S. A Machine-Learning Approach for Detection and Quantification of QRS Fragmentation. IEEE J Biomed Health Inform 2019; 23:1980-1989. [DOI: 10.1109/jbhi.2018.2878492] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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11
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Gooliaff TJ, Hodges KE. Measuring agreement among experts in classifying camera images of similar species. Ecol Evol 2018; 8:11009-11021. [PMID: 30519423 PMCID: PMC6262731 DOI: 10.1002/ece3.4567] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 08/06/2018] [Accepted: 09/03/2018] [Indexed: 11/11/2022] Open
Abstract
Camera trapping and solicitation of wildlife images through citizen science have become common tools in ecological research. Such studies collect many wildlife images for which correct species classification is crucial; even low misclassification rates can result in erroneous estimation of the geographic range or habitat use of a species, potentially hindering conservation or management efforts. However, some species are difficult to tell apart, making species classification challenging-but the literature on classification agreement rates among experts remains sparse. Here, we measure agreement among experts in distinguishing between images of two similar congeneric species, bobcats (Lynx rufus) and Canada lynx (Lynx canadensis). We asked experts to classify the species in selected images to test whether the season, background habitat, time of day, and the visible features of each animal (e.g., face, legs, tail) affected agreement among experts about the species in each image. Overall, experts had moderate agreement (Fleiss' kappa = 0.64), but experts had varying levels of agreement depending on these image characteristics. Most images (71%) had ≥1 expert classification of "unknown," and many images (39%) had some experts classify the image as "bobcat" while others classified it as "lynx." Further, experts were inconsistent even with themselves, changing their classifications of numerous images when they were asked to reclassify the same images months later. These results suggest that classification of images by a single expert is unreliable for similar-looking species. Most of the images did obtain a clear majority classification from the experts, although we emphasize that even majority classifications may be incorrect. We recommend that researchers using wildlife images consult multiple species experts to increase confidence in their image classifications of similar sympatric species. Still, when the presence of a species with similar sympatrics must be conclusive, physical or genetic evidence should be required.
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Affiliation(s)
- TJ Gooliaff
- Department of BiologyUniversity of British Columbia OkanaganKelownaBritish ColumbiaCanada
| | - Karen E. Hodges
- Department of BiologyUniversity of British Columbia OkanaganKelownaBritish ColumbiaCanada
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12
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Robyns T, Nuyens D, Vandenberk B, Kuiperi C, Corveleyn A, Breckpot J, Garweg C, Ector J, Willems R. Genotype-phenotype relationship and risk stratification in loss-of-function SCN5A mutation carriers. Ann Noninvasive Electrocardiol 2018; 23:e12548. [PMID: 29709101 DOI: 10.1111/anec.12548] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 02/12/2018] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION Loss-of-function (LoF) mutations in the SCN5A gene cause multiple phenotypes including Brugada Syndrome (BrS) and a diffuse cardiac conduction defect. Markers of increased risk for sudden cardiac death (SCD) in LoF SCN5A mutation carriers are ill defined. We hypothesized that late potentials and fragmented QRS would be more prevalent in SCN5A mutation carriers compared to SCN5A-negative BrS patients and evaluated risk markers for SCD in SCN5A mutation carriers. METHODS We included all SCN5A loss-of-function mutation carriers and SCN5A-negative BrS patients from our center. A combined arrhythmic endpoint was defined as appropriate ICD shock or SCD. RESULTS Late potentials were more prevalent in 79 SCN5A mutation carriers compared to 39 SCN5A-negative BrS patients (66% versus 44%, p = .021), while there was no difference in the prevalence of fragmented QRS. PR interval prolongation was the only parameter that predicted the presence of a SCN5A mutation in BrS (OR 1.08; p < .001). Four SCN5A mutation carriers, of whom three did not have a diagnostic type 1 ECG either spontaneously or after provocation with a sodium channel blocker, reached the combined arrhythmic endpoint during a follow-up of 44 ± 52 months resulting in an annual incidence rate of 1.37%. CONCLUSION LP were more frequently observed in SCN5A mutation carriers, while fQRS was not. In SCN5A mutation carriers, the annual incidence rate of SCD was non-negligible, even in the absence of a spontaneous or induced type 1 ECG. Therefore, proper follow-up of SCN5A mutation carriers without Brugada syndrome phenotype is warranted.
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Affiliation(s)
- Tomas Robyns
- Department of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium.,Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Dieter Nuyens
- Department of Cardiology, Ziekenhuis Oost Limburg, Genk, Belgium
| | - Bert Vandenberk
- Department of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium.,Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Cuno Kuiperi
- Department of Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - Anniek Corveleyn
- Department of Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - Jeroen Breckpot
- Department of Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - Christophe Garweg
- Department of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium.,Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Joris Ector
- Department of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium.,Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Rik Willems
- Department of Cardiovascular Diseases, University Hospitals Leuven, Leuven, Belgium.,Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
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