T Wave Alternans

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David S Rosenbaum - One of the best experts on this subject based on the ideXlab platform.

  • Can we alTernaTe beTween T-Wave alTernans TesTing meThods?
    Heart rhythm, 2009
    Co-Authors: Guy Amit, Otto Costantini, David S Rosenbaum
    Abstract:

    To The EdiTor: The commenTs by Drs. Verrier, Kumar, and Nearing are well Taken. Indeed, The modified moving average (MMA) meThod for deTecTing T Wave alTernans has incorporaTed Techniques in an aTTempT To compensaTe for various sources of noise which mighT oTherwise obscure The disTincTion beTween T Wave alTernans and noise. However, major and fundamenTal unresolved quesTions remain; When subjecT To The usual sTandards applied To The evaluaTion of a diagnosTic TesT, will The MMA meThod predicT ouTcomes? Can MMA predicT ouTcomes as well or beTTer Than esTablished meThods for measuring T Wave alTernans? Is There any scienTific, TheoreTical, or pracTical jusTificaTion for using The MMA meThod in The firsT place? The only way To answer quesTions 1 and 2 is by sTandardizing The MMA meThod, esTablishing, a priori, rigorous criTeria for MMA TesT posiTiviTy (including means for accounTing for raTe dependence of T Wave alTernans), and Then applying These TesTing criTeria prospecTively To independenT paTienT populaTions. IT is also essenTial ThaT evenTs are adjudicaTed by invesTigaTors who are blinded To The ouTcome of The MMA TesT resulT. These are The same sTandards any diagnosTic TesT musT fulfill before The TesT can be uTilized in larger clinical Trials, leT alone clinical pracTice. In Terms of quesTion number 3, The scienTific raTionale for measuring T Wave alTernans wiTh The MMA meThod remains elusive. IT offers no TheoreTical or pracTical advanTages over exisTing and well validaTed meThods for measuring T Wave alTernans. The noTion ThaT MMA offers some benefiT because iT can measure T Wave alTernans from an ambulaTory HolTer is false. The mode of ECG acquisiTion is unrelaTed To The meThod of signal processing applied To The ECG daTa. Clearly, new and beTTer meThods for idenTifying paTienTs aT risk for sudden cardiac deaTh are badly needed. However, progress will require innovaTions ThaT offer genuine advanTages over exisTing Techniques, and The applicaTion of rigorous scienTific meThods To ascerTain The value of The Technique in relevanT paTienT populaTions.

  • Influence of hearT raTe and sympaTheTic sTimulaTion on arrhyThmogenic T Wave alTernans
    American journal of physiology. Heart and circulatory physiology, 2000
    Co-Authors: Elizabeth S. Kaufman, Judith A. Mackall, Birendra Julka, Carole Drabek, David S Rosenbaum
    Abstract:

    We deTermined The Temporal sTabiliTy of T Wave alTernans (TWA) during consTanT raTe sTimulaTion and The dependence of alTernans on hearT raTe (HR) and β-adrenergic sTimulaTion. AlThough iT is esTab...

  • mechanism linking T Wave alTernans To The genesis of cardiac fibrillaTion
    Circulation, 1999
    Co-Authors: Joseph M Pastore, Fadi G Akar, Steven D Girouard, Kenneth R Laurita, David S Rosenbaum
    Abstract:

    Background—AlThough T-Wave alTernans has been closely associaTed wiTh vulnerabiliTy To venTricular arrhyThmias, The cellular processes underlying T-Wave alTernans and Their role, if any, in The mechanism of reenTry remain unclear. MeThods and ResulTs—T-Wave alTernans on The surface ECG was eliciTed in 8 Langendorff-perfused guinea pig hearTs during fixed-raTe pacing while acTion poTenTials were recorded simulTaneously from 128 epicardial siTes wiTh volTage-sensiTive dyes. AlTernans of The repolarizaTion phase of The acTion poTenTial was observed above a criTical Threshold hearT raTe (HR) (209±46 bpm) ThaT was significanTly lower (by 57±36 bpm) Than The HR Threshold for alTernaTion of acTion poTenTial depolarizaTion. The magniTude (range, 2.7 To 47.0 mV) and HR Threshold (range, 171 To 272 bpm) of repolarizaTion alTernans varied subsTanTially beTween cells across The epicardial surface. T-Wave alTernans on The surface ECG was explained primarily by beaT-To-beaT alTernaTion in The Time course of cellular re...

  • T Wave alTernans and dispersion of The qT inTerval as risk sTraTificaTion markers in paTienTs suscepTible To susTained venTricular arrhyThmias
    American Journal of Cardiology, 1998
    Co-Authors: Antonis A Armoundas, David S Rosenbaum, Motohisa Osaka, Theofanie Mela, Jeremy N Ruskin, Hasan Garan, Richard J Cohen
    Abstract:

    T-Wave alTernans and QT dispersion were compared as predicTors of The ouTcome of elecTrophysiologic sTudy and arrhyThmia-free survival in paTienTs undergoing elecTrophysiologic evaluaTion. T-Wave alTernans was a highly significanT predicTor of These 2 ouTcome variables, whereas QT dispersion was noT.

  • OcculT T Wave AlTernans in Long QT Syndrome
    Journal of cardiovascular electrophysiology, 1996
    Co-Authors: Simie B. Platt, Johan M. Vijgen, Paul Albrecht, George F. Van Hare, Mark D. Carlson, David S Rosenbaum
    Abstract:

    T Wave AlTernans in LQTS. T Wave alTernans ThaT is visually apparenT on The ECG is a known risk facTor for sudden deaTh in idiopaThic long QT syndrome (LQTS). To deTermine if occulT and visually undeTecTable forms of T Wave alTernans are also presenT in LQTS, we measured T Wave alTernans from a 16-year-old girl wiTh LQTS during exercise using specTral analysis meThods and a recording sysTem designed To minimize exercise-relaTed noise. While There was no alTernans aT resT, sTaTisTically significanT, yeT visually inapparenT T Wave alTernans were measured boTh during exercise and recovery. Using idenTical recording Techniques, no significanT T Wave alTernans was deTecTed from The subjecT's moTher, who had a prolonged QT inTerval buT was noT experiencing arrhyThmias, nor from five healThy volunTeers wiTh normal QT inTervals. This reporT suggesTs ThaT elecTrocardiographically occulT, yeT prognosTically imporTanT forms of T Wave alTernans may be presenT in paTienTs wiTh LQTS.

Richard J Cohen - One of the best experts on this subject based on the ideXlab platform.

  • can microvolT T Wave alTernans TesTing reduce unnecessary defibrillaTor implanTaTion
    Nature Reviews Cardiology, 2005
    Co-Authors: Antonis A Armoundas, Stefan H Hohnloser, Takanori Ikeda, Richard J Cohen
    Abstract:

    As defibrillaTor Therapy is invasive and expensive, using a defibrillaTor as primary prevenTion Therapy requires risk sTraTificaTion To idenTify suiTable paTienTs aT significanT risk. In This review AnTonis A Armoundas eT al evaluaTe wheTher clinical daTa supporT The use of microvolT T-Wave alTernans TesTing To idenTify paTienTs who are unlikely To benefiT from primary prevenTion implanTable cardioverTer-defibrillaTor Therapy.

  • T Wave alTernans negaTive coronary paTienTs wiTh low ejecTion and benefiT from defibrillaTor implanTaTion
    The Lancet, 2003
    Co-Authors: Stefan H Hohnloser, Daniel M. Bloomfield, Takanori Ikeda, Omar H Dabbous, Richard J Cohen
    Abstract:

    In a Trial of prophylacTic implanTaTion of a defibrillaTor, a morTaliTy benefiT was seen among paTienTs wiTh previous myocardial infarcTion and a lefT-venTricular ejecTion fracTion of 0·30 or less. We idenTified 129 similar paTienTs from Two previously published clinical Trials in which microvolT T-Wave alTernans TesTing was prospecTively assessed. AT 24 monThs of follow-up, no sudden cardiac deaTh or cardiac arresT was seen among paTienTs who TesTed T-Wave alTernans negaTive, compared wiTh an evenT raTe of 15·6% among The remaining paTienTs. TesTing of T-Wave alTernans seems To idenTify paTienTs who are aT low risk of venTricular TachyarrhyThmic evenT and who may noT benefiT from defibrillaTor Therapy.

  • inTerpreTaTion and classificaTion of microvolT T Wave alTernans TesTs
    Journal of Cardiovascular Electrophysiology, 2002
    Co-Authors: M Daniel M D Bloomfield, H Stefan M D Hohnloser, Richard J Cohen
    Abstract:

    InTerpreTaTion of T Wave AlTernans TesTs. MeasuremenT of microvolT-level T Wave alTernans (TWA) during rouTine exercise sTress TesTing now is possible as a resulT of sophisTicaTed noise reducTion Techniques and analyTic meThods ThaT have become commercially available. Even Though This Technology is new, The available daTa suggesT ThaT microvolT TWA is a poTenT predicTor of arrhyThmia risk in diverse disease sTaTes. As This Technology becomes more widely available, physicians will be called upon To inTerpreT microvolT TWA Tracings. This review seeks To esTablish uniform sTandards for The clinical inTerpreTaTion of microvolT TWA Tracings.

  • T Wave AlTernans Threshold in Normal Children
    Journal of cardiovascular electrophysiology, 2001
    Co-Authors: Michael Cheung, Richard J Cohen, Andrew M. Davis, James L. Wilkinson
    Abstract:

    T Wave AlTernans in Children.InTroducTion: SusTained microvolT-level T Wave alTernans (TWA) during exercise is a predicTor of venTricular arrhyThmia propensiTy in adulT populaTions. TWA occurs in normal adulTs, buT iT is rare aT < 70% of predicTed maximum hearT raTe. An onseT hearT raTe ≤ 110 is believed To be significanT. The aim of This sTudy was To examine The feasibiliTy of performing The TesT in children and To deTermine The normal hearT raTe Threshold for susTained TWA in children. MeThods and ResulTs: AlTernans was evaluaTed during bicycle exercise in 100 normal volunTeers aged 8 To 17 years. AdequaTe resTing daTa were obTained in 76 of 100 children and was negaTive in all. Exercise daTa from 16 of 100 was excluded due To excessive noise. Median maximum hearT raTe was 192 (range 140 To 214). SusTained alTernans was absenT in 75 (89%) of 84. In The nine children wiTh susTained alTernans, median onseT hearT raTe was 138 (range 120 To 158), and 7 of 9 had an onseT hearT raTe ≤ 135. Median hearT raTe Threshold as a percenTage of predicTed maximum hearT raTe (220 – age) was 67% (range 58% To 76%). Only 1 subjecT (1.2%) had an onseT hearT raTe < 60% of predicTed maximum. There was no significanT difference beTween age, gender, endurance, maximum hearT raTe, QRS duraTion, QT inTerval, or QTc in Those wiTh and Those wiThouT susTained TWA. Conclusion: Noninvasive assessmenT of TWA is feasible aT ≤ 8 years of age. SusTained TWA was presenT in 11% of normal children, buT was absenT aT hearT raTes below 120 and rare (1.2%) below 60% of predicTed maximum hearT raTe.

  • predicTive value of T Wave alTernans for arrhyThmic evenTs in paTienTs wiTh congesTive hearT failure
    The Lancet, 2000
    Co-Authors: Thomas Klingenheben, Ralph B Dagostino, Markus Zabel, Richard J Cohen, Stefan H Hohnloser
    Abstract:

    Summary MeasuremenT of microvolT level T-Wave alTernans in The surface elecTrocardiogram is a novel way To assess The risk of venTricular arrhyThmias. Seven TesTs of arrhyThmic risk, including T-Wave alTernans, were underTaken in 107 consecuTive paTienTs wiTh congesTive hearT failure and no hisTory of susTained venTricular arrhyThmias; The paTienTs were followed up for arrhyThmic evenTs during The nexT 18 monThs. Of The paTienTs wiTh evenTs, 11 had posiTive and Two indeTerminaTe T-Wave alTernans resulTs; There were no arrhyThmic evenTs among paTienTs wiTh negaTive T-Wave alTernans resulTs. Of The seven TesTs, only T-Wave alTernans was a significanT (p=0·0036) and independenT predicTor of arrhyThmic evenTs.

John E. Madias - One of the best experts on this subject based on the ideXlab platform.

  • Spinal cord sTimulaTion and T-Wave alTernans.
    Europace, 2008
    Co-Authors: John E. Madias
    Abstract:

    Ferrero eT al. 1 in a sTudy published online in The Europace Journal evaluaTed T-Wave alTernans (TWA) before and afTer spinal cord sTimulaTion (SCS) To ascerTain wheTher This SCS alTers The arrhyThmic subsTraTe and Thus has an effecT on TWA. The auThors evaluaTed Three paTienTs wiTh ischaemic cardiomyopaThy, who had undergone implanTaTion of boTh implanTable cardioverTer/defibrillaTor (ICD) for sudden cardiac deaTh prophylaxis and an SCS device for inTracTable angina. T-Wave alTernans was eliciTed during pacing via The ICDs while …

  • T-Wave alTernans and inTravenTricular conducTion delays.
    Journal of the American College of Cardiology, 2008
    Co-Authors: John E. Madias
    Abstract:

    I read wiTh greaT inTeresT The sTudy by CanTillon eT al. ([1][1]) on The uTiliTy of microvolT T-Wave alTernans (MTWA) in predicTing ToTal morTaliTy and arrhyThmia-free survival in paTienTs wiTh a lefT venTricular ejecTion fracTion ≤30% who had been referred for invasive elecTrophysiological

Roman Maniewski - One of the best experts on this subject based on the ideXlab platform.

  • The roles of mid-myocardial and epicardial cells in T-Wave alTernans developmenT: a simulaTion sTudy
    BioMedical Engineering OnLine, 2018
    Co-Authors: Darius Janusek, J. Svehlikova, J. Zelinka, W. Weigl, R. Zaczek, G. Opolski, M. Tysler, Roman Maniewski
    Abstract:

    Background The occurrence of T-Wave alTernans in elecTrocardiographic signals was recenTly linked To suscepTibiliTy To venTricular arrhyThmias and sudden cardiac deaTh. Thus, by deTecTing and comprehending The origins of T-Wave alTernans, iT mighT be possible To prevenT such evenTs. ResulTs Here, we simulaTed T-Wave alTernans in a compuTer-generaTed human hearT model by modulaTing The acTion poTenTial duraTion and ampliTude during The firsT parT of The repolarizaTion phase. We hypoThesized ThaT changes in The inTracardiac alTernans paTTerns of acTion poTenTial properTies would differenTially influence T-Wave alTernans measuremenTs aT The body surface. Specifically, changes were simulaTed globally in The whole lefT and righT venTricles To simulaTe concordanT T-Wave alTernans, and locally in selecTed regions To simulaTe discordanT and regional discordanT, hereinafTer referred To as “regional”, T-Wave alTernans. Body surface poTenTial maps and 12-lead elecTrocardiographic signals were Then compuTed. In depTh discriminaTion, The influence of epicardial layers on T-Wave alTernans developmenT was significanTly higher Than ThaT of mid-myocardial cells. Meanwhile, spaTial discriminaTion revealed ThaT discordanT and regional acTion poTenTial properTy changes had a higher influence on T-Wave alTernans ampliTude Than concordanT changes. NoTably, varying T-Wave alTernans sources yielded disTincT body surface poTenTial map paTTerns for T-Wave alTernans ampliTude, which can be used for locaTion of regions wiThin hearTs exhibiTing impaired repolarizaTion. The highesT abiliTy for T-Wave alTernans deTecTion was achieved in lead V1. UlTimaTely, we proposed new parameTers VecTor MagniTude AlTernans and VecTor Angle AlTernans , wiTh higher abiliTy for T-Wave alTernans deTecTion when using mulTi-lead elecTrocardiographic signals processing Than for single leads. Finally, QT alTernans was found To be associaTed wiTh The process of T-Wave alTernans generaTion. Conclusions The disTribuTions of The body surface T-Wave alTernans ampliTude have been shown To have unique paTTerns depending on The Type of alTernans (concordanT, discordanT or regional) and The locaTion of The disTurbance in The hearT. The influence of epicardial cells on T-Wave alTernans developmenT is significanTly higher Than ThaT of mid-myocardial cells, among which The sub-endocardial layer exerTed The highesT influence. QT inTerval alTernans is idenTified as a phenomenon ThaT correlaTe wiTh T-Wave alTernans.

  • The roles of mid-myocardial and epicardial cells in T-Wave alTernans developmenT: a simulaTion sTudy
    Biomedical engineering online, 2018
    Co-Authors: Darius Janusek, J. Svehlikova, J. Zelinka, W. Weigl, M. Tysler, Rajmund Zaczek, Grzegorz Opolski, Roman Maniewski
    Abstract:

    Background The occurrence of T-Wave alTernans in elecTrocardiographic signals was recenTly linked To suscepTibiliTy To venTricular arrhyThmias and sudden cardiac deaTh. Thus, by deTecTing and comprehending The origins of T-Wave alTernans, iT mighT be possible To prevenT such evenTs.

  • EvaluaTion of T-Wave alTernans in high-resoluTion ECG maps recorded during The sTress TesT in paTienTs afTer myocardial infarcTion.
    Archives of medical science : AMS, 2014
    Co-Authors: Darius Janusek, Michal Kania, Rajmund Zaczek, Grzegorz Opolski, Małgorzata Kobylecka, Marek Chojnowski, Leszek Królicki, Roman Maniewski
    Abstract:

    INTRODUCTION RecenT sTudies poinT To analysis of T-Wave alTernans as a promising indicaTor of an increased risk of life-ThreaTening venTricular arrhyThmias. In This sTudy The occurrence of T-Wave alTernans in The high-resoluTion ECGs recorded during The exercise sTress TesT and scinTigraphic TesTs (SPECT) in paTienTs wiTh ischemic hearT disease was examined. MATERIAL AND METHODS The sTudy group consisTed of 33 paTienTs afTer myocardial infarcTion. In The group of paTienTs afTer myocardial infarcTion and wiTh low lefT venTricular ejecTion fracTion correlaTions of 70% beTween The TesT resulTs of T-Wave alTernans and SPECT and 60% beTween The TesT resulTs of T-Wave alTernans and sTress TesT were found. RESULTS In The group of paTienTs afTer myocardial infarcTion buT wiTh high lefT venTricular ejecTion fracTion correlaTions were respecTively 39% and 48%. The analysis of The elecTrocardiographic maps showed a sTrong dependence of This correlaTion on The T-Wave alTernans ampliTude and locaTion of The ECG measuring elecTrode on The chesT. The resulTs mighT suggesT ThaT in paTienTs afTer myocardial infarcTion and aT increased risk for sudden cardiac deaTh T-Wave alTernans may also provide informaTion abouT cardiac elecTrical insTabiliTy associaTed wiTh ischemia. CONCLUSIONS IT can also be assumed ThaT The posiTion of The elecTrode where The highesT level of The T-Wave alTernans was deTecTed can indicaTe The locaTion of The ischemic region of The hearT.

  • BIBE - EvaluaTion of T-Wave alTernans in comparison wiTh ECG sTress TesT and scinTigraphic examinaTion in paTienTs wiTh coronary arTery disease
    2012 IEEE 12th International Conference on Bioinformatics & Bioengineering (BIBE), 2012
    Co-Authors: Darius Janusek, Roman Maniewski, Michal Kania, Rajmund Zaczek, H. Zavala-fernandez, Grzegorz Opolski, Małgorzata Kobylecka, Leszek Królicki
    Abstract:

    The resulTs of sTudy on T-Wave alTernans in The group of paTienTs wiTh ischemic hearT disease are shown. The body surface poTenTial maps were recorded wiTh use of 67 channel high-resoluTion ECG sysTem. ElecTrocardiographic sTress TesT was performed during The paTienT examinaTions. The T-Wave alTernans raTio was calculaTed and resulTs were compared wiTh daTa obTained by single-phoTon emission compuTed Tomography (SPECT). SignificanT correlaTions beTween resulTs of T-Wave alTernans analysis and SPECT TesT have been found.

  • ApplicaTion of WaveleT Based Denoising for T-Wave AlTernans Analysis in High ResoluTion ECG Maps
    Measurement Science Review, 2011
    Co-Authors: Darius Janusek, Michal Kania, Rajmund Zaczek, H. Zavala-fernandez, Anna Zbieć, Grzegorz Opolski, Roman Maniewski
    Abstract:

    T-Wave alTernans (TWA) allows for idenTificaTion of paTienTs aT an increased risk of venTricular arrhyThmia. STress TesT, which increases hearT raTe in conTrolled manner, is used for TWA measuremenT. However, The TWA deTecTion and analysis are ofTen disTurbed by muscular inTerference. The evaluaTion of WaveleT based denoising meThods was performed To find opTimal algoriThm for TWA analysis. ECG signals recorded in Twelve paTienTs wiTh cardiac disease were analyzed. In seven of Them significanT T-Wave alTernans magniTude was deTecTed. The applicaTion of WaveleT based denoising meThod in The pre-processing sTage increases The T-Wave alTernans magniTude as well as The number of BSPM signals where TWA was deTecTed. Keywords: T-Wave alTernans, WaveleT denoising, sTress TesT, arrhyThmia, sudden cardiac deaTh

Darius Janusek - One of the best experts on this subject based on the ideXlab platform.

  • The roles of mid-myocardial and epicardial cells in T-Wave alTernans developmenT: a simulaTion sTudy
    BioMedical Engineering OnLine, 2018
    Co-Authors: Darius Janusek, J. Svehlikova, J. Zelinka, W. Weigl, R. Zaczek, G. Opolski, M. Tysler, Roman Maniewski
    Abstract:

    Background The occurrence of T-Wave alTernans in elecTrocardiographic signals was recenTly linked To suscepTibiliTy To venTricular arrhyThmias and sudden cardiac deaTh. Thus, by deTecTing and comprehending The origins of T-Wave alTernans, iT mighT be possible To prevenT such evenTs. ResulTs Here, we simulaTed T-Wave alTernans in a compuTer-generaTed human hearT model by modulaTing The acTion poTenTial duraTion and ampliTude during The firsT parT of The repolarizaTion phase. We hypoThesized ThaT changes in The inTracardiac alTernans paTTerns of acTion poTenTial properTies would differenTially influence T-Wave alTernans measuremenTs aT The body surface. Specifically, changes were simulaTed globally in The whole lefT and righT venTricles To simulaTe concordanT T-Wave alTernans, and locally in selecTed regions To simulaTe discordanT and regional discordanT, hereinafTer referred To as “regional”, T-Wave alTernans. Body surface poTenTial maps and 12-lead elecTrocardiographic signals were Then compuTed. In depTh discriminaTion, The influence of epicardial layers on T-Wave alTernans developmenT was significanTly higher Than ThaT of mid-myocardial cells. Meanwhile, spaTial discriminaTion revealed ThaT discordanT and regional acTion poTenTial properTy changes had a higher influence on T-Wave alTernans ampliTude Than concordanT changes. NoTably, varying T-Wave alTernans sources yielded disTincT body surface poTenTial map paTTerns for T-Wave alTernans ampliTude, which can be used for locaTion of regions wiThin hearTs exhibiTing impaired repolarizaTion. The highesT abiliTy for T-Wave alTernans deTecTion was achieved in lead V1. UlTimaTely, we proposed new parameTers VecTor MagniTude AlTernans and VecTor Angle AlTernans , wiTh higher abiliTy for T-Wave alTernans deTecTion when using mulTi-lead elecTrocardiographic signals processing Than for single leads. Finally, QT alTernans was found To be associaTed wiTh The process of T-Wave alTernans generaTion. Conclusions The disTribuTions of The body surface T-Wave alTernans ampliTude have been shown To have unique paTTerns depending on The Type of alTernans (concordanT, discordanT or regional) and The locaTion of The disTurbance in The hearT. The influence of epicardial cells on T-Wave alTernans developmenT is significanTly higher Than ThaT of mid-myocardial cells, among which The sub-endocardial layer exerTed The highesT influence. QT inTerval alTernans is idenTified as a phenomenon ThaT correlaTe wiTh T-Wave alTernans.

  • The roles of mid-myocardial and epicardial cells in T-Wave alTernans developmenT: a simulaTion sTudy
    Biomedical engineering online, 2018
    Co-Authors: Darius Janusek, J. Svehlikova, J. Zelinka, W. Weigl, M. Tysler, Rajmund Zaczek, Grzegorz Opolski, Roman Maniewski
    Abstract:

    Background The occurrence of T-Wave alTernans in elecTrocardiographic signals was recenTly linked To suscepTibiliTy To venTricular arrhyThmias and sudden cardiac deaTh. Thus, by deTecTing and comprehending The origins of T-Wave alTernans, iT mighT be possible To prevenT such evenTs.

  • EvaluaTion of T-Wave alTernans in high-resoluTion ECG maps recorded during The sTress TesT in paTienTs afTer myocardial infarcTion.
    Archives of medical science : AMS, 2014
    Co-Authors: Darius Janusek, Michal Kania, Rajmund Zaczek, Grzegorz Opolski, Małgorzata Kobylecka, Marek Chojnowski, Leszek Królicki, Roman Maniewski
    Abstract:

    INTRODUCTION RecenT sTudies poinT To analysis of T-Wave alTernans as a promising indicaTor of an increased risk of life-ThreaTening venTricular arrhyThmias. In This sTudy The occurrence of T-Wave alTernans in The high-resoluTion ECGs recorded during The exercise sTress TesT and scinTigraphic TesTs (SPECT) in paTienTs wiTh ischemic hearT disease was examined. MATERIAL AND METHODS The sTudy group consisTed of 33 paTienTs afTer myocardial infarcTion. In The group of paTienTs afTer myocardial infarcTion and wiTh low lefT venTricular ejecTion fracTion correlaTions of 70% beTween The TesT resulTs of T-Wave alTernans and SPECT and 60% beTween The TesT resulTs of T-Wave alTernans and sTress TesT were found. RESULTS In The group of paTienTs afTer myocardial infarcTion buT wiTh high lefT venTricular ejecTion fracTion correlaTions were respecTively 39% and 48%. The analysis of The elecTrocardiographic maps showed a sTrong dependence of This correlaTion on The T-Wave alTernans ampliTude and locaTion of The ECG measuring elecTrode on The chesT. The resulTs mighT suggesT ThaT in paTienTs afTer myocardial infarcTion and aT increased risk for sudden cardiac deaTh T-Wave alTernans may also provide informaTion abouT cardiac elecTrical insTabiliTy associaTed wiTh ischemia. CONCLUSIONS IT can also be assumed ThaT The posiTion of The elecTrode where The highesT level of The T-Wave alTernans was deTecTed can indicaTe The locaTion of The ischemic region of The hearT.

  • BIBE - EvaluaTion of T-Wave alTernans in comparison wiTh ECG sTress TesT and scinTigraphic examinaTion in paTienTs wiTh coronary arTery disease
    2012 IEEE 12th International Conference on Bioinformatics & Bioengineering (BIBE), 2012
    Co-Authors: Darius Janusek, Roman Maniewski, Michal Kania, Rajmund Zaczek, H. Zavala-fernandez, Grzegorz Opolski, Małgorzata Kobylecka, Leszek Królicki
    Abstract:

    The resulTs of sTudy on T-Wave alTernans in The group of paTienTs wiTh ischemic hearT disease are shown. The body surface poTenTial maps were recorded wiTh use of 67 channel high-resoluTion ECG sysTem. ElecTrocardiographic sTress TesT was performed during The paTienT examinaTions. The T-Wave alTernans raTio was calculaTed and resulTs were compared wiTh daTa obTained by single-phoTon emission compuTed Tomography (SPECT). SignificanT correlaTions beTween resulTs of T-Wave alTernans analysis and SPECT TesT have been found.

  • ApplicaTion of WaveleT Based Denoising for T-Wave AlTernans Analysis in High ResoluTion ECG Maps
    Measurement Science Review, 2011
    Co-Authors: Darius Janusek, Michal Kania, Rajmund Zaczek, H. Zavala-fernandez, Anna Zbieć, Grzegorz Opolski, Roman Maniewski
    Abstract:

    T-Wave alTernans (TWA) allows for idenTificaTion of paTienTs aT an increased risk of venTricular arrhyThmia. STress TesT, which increases hearT raTe in conTrolled manner, is used for TWA measuremenT. However, The TWA deTecTion and analysis are ofTen disTurbed by muscular inTerference. The evaluaTion of WaveleT based denoising meThods was performed To find opTimal algoriThm for TWA analysis. ECG signals recorded in Twelve paTienTs wiTh cardiac disease were analyzed. In seven of Them significanT T-Wave alTernans magniTude was deTecTed. The applicaTion of WaveleT based denoising meThod in The pre-processing sTage increases The T-Wave alTernans magniTude as well as The number of BSPM signals where TWA was deTecTed. Keywords: T-Wave alTernans, WaveleT denoising, sTress TesT, arrhyThmia, sudden cardiac deaTh