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Tereshchenko LG, Waks JW, Tompkins C, Rogers AJ, Ehdaie A, Henrikson CA, Dalouk K, Raitt M, Kewalramani S, Kattan MW, Santangeli P, Wilkoff BW, Kapadia SR, Narayan SM, Chugh SS. Competing risks of monomorphic vs. non-monomorphic ventricular arrhythmias in primary prevention implantable cardioverter-defibrillator recipients: Global Electrical Heterogeneity and Clinical Outcomes (GEHCO) study. Europace 2024; 26:euae127. [PMID: 38703375 PMCID: PMC11167666 DOI: 10.1093/europace/euae127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 02/09/2024] [Accepted: 03/29/2024] [Indexed: 05/06/2024] Open
Abstract
AIMS Ablation of monomorphic ventricular tachycardia (MMVT) has been shown to reduce shock frequency and improve survival. We aimed to compare cause-specific risk factors for MMVT and polymorphic ventricular tachycardia (PVT)/ventricular fibrillation (VF) and to develop predictive models. METHODS AND RESULTS The multicentre retrospective cohort study included 2668 patients (age 63.1 ± 13.0 years; 23% female; 78% white; 43% non-ischaemic cardiomyopathy; left ventricular ejection fraction 28.2 ± 11.1%). Cox models were adjusted for demographic characteristics, heart failure severity and treatment, device programming, and electrocardiogram metrics. Global electrical heterogeneity was measured by spatial QRS-T angle (QRSTa), spatial ventricular gradient elevation (SVGel), azimuth, magnitude (SVGmag), and sum absolute QRST integral (SAIQRST). We compared the out-of-sample performance of the lasso and elastic net for Cox proportional hazards and the Fine-Gray competing risk model. During a median follow-up of 4 years, 359 patients experienced their first sustained MMVT with appropriate implantable cardioverter-defibrillator (ICD) therapy, and 129 patients had their first PVT/VF with appropriate ICD shock. The risk of MMVT was associated with wider QRSTa [hazard ratio (HR) 1.16; 95% confidence interval (CI) 1.01-1.34], larger SVGel (HR 1.17; 95% CI 1.05-1.30), and smaller SVGmag (HR 0.74; 95% CI 0.63-0.86) and SAIQRST (HR 0.84; 95% CI 0.71-0.99). The best-performing 3-year competing risk Fine-Gray model for MMVT [time-dependent area under the receiver operating characteristic curve (ROC(t)AUC) 0.728; 95% CI 0.668-0.788] identified high-risk (> 50%) patients with 75% sensitivity and 65% specificity, and PVT/VF prediction model had ROC(t)AUC 0.915 (95% CI 0.868-0.962), both satisfactory calibration. CONCLUSION We developed and validated models to predict the competing risks of MMVT or PVT/VF that could inform procedural planning and future randomized controlled trials of prophylactic ventricular tachycardia ablation. CLINICAL TRIAL REGISTRATION URL:www.clinicaltrials.gov Unique identifier:NCT03210883.
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Affiliation(s)
- Larisa G Tereshchenko
- Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave, JJN3-01, Cleveland, OH, USA
- Department of Cardiovascular Medicine, Heart, Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jonathan W Waks
- Department of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Christine Tompkins
- Department of Cardiovascular Medicine, University of Colorado, Aurora, CO, USA
| | - Albert J Rogers
- Department of Cardiovascular Medicine, Stanford University, Palo Alto, CA, USA
| | - Ashkan Ehdaie
- Department of Cardiovascular Medicine, Cedars-Sinai Health System, Los Angeles, CA, USA
| | - Charles A Henrikson
- Department of Cardiovascular Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Khidir Dalouk
- Department of Cardiovascular Medicine, VA Portland Health Care System, OR, USA
| | - Merritt Raitt
- Department of Cardiovascular Medicine, VA Portland Health Care System, OR, USA
| | - Shivangi Kewalramani
- Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave, JJN3-01, Cleveland, OH, USA
| | - Michael W Kattan
- Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Ave, JJN3-01, Cleveland, OH, USA
| | - Pasquale Santangeli
- Department of Cardiovascular Medicine, Heart, Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Bruce W Wilkoff
- Department of Cardiovascular Medicine, Heart, Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Samir R Kapadia
- Department of Cardiovascular Medicine, Heart, Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Sanjiv M Narayan
- Department of Cardiovascular Medicine, Stanford University, Palo Alto, CA, USA
| | - Sumeet S Chugh
- Department of Cardiovascular Medicine, Cedars-Sinai Health System, Los Angeles, CA, USA
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2
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Vondrak J, Penhaker M. Review of Processing Pathological Vectorcardiographic Records for the Detection of Heart Disease. Front Physiol 2022; 13:856590. [PMID: 36213240 PMCID: PMC9536877 DOI: 10.3389/fphys.2022.856590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/04/2022] [Indexed: 11/23/2022] Open
Abstract
Vectorcardiography (VCG) is another useful method that provides us with useful spatial information about the electrical activity of the heart. The use of vectorcardiography in clinical practice is not common nowadays, mainly due to the well-established 12-lead ECG system. However, VCG leads can be derived from standard 12-lead ECG systems using mathematical transformations. These derived or directly measured VCG records have proven to be a useful tool for diagnosing various heart diseases such as myocardial infarction, ventricular hypertrophy, myocardial scars, long QT syndrome, etc., where standard ECG does not achieve reliable accuracy within automated detection. With the development of computer technology in recent years, vectorcardiography is beginning to come to the forefront again. In this review we highlight the analysis of VCG records within the extraction of functional parameters for the detection of heart disease. We focus on methods of processing VCG functionalities and their use in given pathologies. Improving or combining current or developing new advanced signal processing methods can contribute to better and earlier detection of heart disease. We also focus on the most commonly used methods to derive a VCG from 12-lead ECG.
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Affiliation(s)
- Jaroslav Vondrak
- Faculty of Electrical Engineering and Computer Science, VSB-Technical University of Ostrava, Ostrava, Czech Republic
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3
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Wang Y, Yin X, Liang X, Chen Y, Pan S, Chen Z, Tse G, Geng X, Liu T. Three-dimensional vectorcardiographic characteristics of breast cancer patients treated with chemotherapy. J Electrocardiol 2021; 67:23-30. [PMID: 34000614 DOI: 10.1016/j.jelectrocard.2021.04.018] [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: 02/18/2021] [Revised: 04/25/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND Patients receiving chemotherapy for breast cancer (breast cancer) may develop cardiac electrophysiological abnormalities. The aim of this study is to examined possible alterations in cardiac electrophysiological parameters detected by three-dimensional vectorcardiograms (3D-VCGs) in breast cancer patients who received chemotherapy. METHODS This was a prospective single-center cohort study conducted in Fourth Hospital of Hebei Medical University, China. Patients with breast cancer referred for chemotherapy from May 1, 2019, to October 1, 2019 were invited to participate in the study. 3D-VCGs and echocardiography were recorded at rest four times (baseline, after the first cycle, after third cycles and at the end of the regimen, respectively). RESULTS A total of 63 patients were included. Compared with baseline, decreases in 3D maximum T vector magnitude (TVM) (0.29 ± 0.10 vs. 0.25 ± 0.10 mV; p < 0.05) and 3D T/QRS ratio (0.26 ± 0.11 vs. 0.21 ± 0.11; p < 0.05) were observed by the end of chemotherapy regimen, while echocardiographic parameters showed no significant variation before and after chemotherapy (all P > 0.05). Furthermore, after third cycles, maximum TVM were correlated with LVEF except in horizontal plane (3D: r = 0.33, p < 0.01; frontal plane: r = 0.34, p < 0.01; horizontal plane: r = 0.24, p = 0.06; right side plane: r = 0.30, p = 0.02). After completion of chemotherapy, maximum TVM were also positive correlated with LVEF (3D: r = 0.33, P < 0.01; frontal plane: r = 0.32, P = 0.01; horizontal plane: r = 0.27, P = 0.03, right side plane: r = 0.38, P < 0.01). CONCLUSIONS Along with chemotherapy, maximum TVM and T/QRS is lower in patients with breast cancer. After third cycles and after completion of chemotherapy, there is a positive correlation between maximum TVM and LVEF. 3D-VCGs can be used to detect electrophysiological abnormalities in breast cancer patients receiving chemotherapy.
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Affiliation(s)
- Yueying Wang
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China
| | - Xi Yin
- Department of Function, Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, PR China
| | - Xufei Liang
- Department of Function, Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, PR China
| | - Yongzhen Chen
- Department of Function, Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, PR China
| | - Shuo Pan
- Department of Function, Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, PR China
| | - Ziliang Chen
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China
| | - Gary Tse
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China
| | - Xuhong Geng
- Department of Function, Fourth Hospital of Hebei Medical University, Shijiazhuang 050011, PR China.
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, PR China.
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4
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Hézső T, Naveed M, Dienes C, Kiss D, Prorok J, Árpádffy-Lovas T, Varga R, Fujii E, Mercan T, Topal L, Kistamás K, Szentandrássy N, Almássy J, Jost N, Magyar J, Bányász T, Baczkó I, Varró A, Nánási PP, Virág L, Horváth B. Mexiletine-like cellular electrophysiological effects of GS967 in canine ventricular myocardium. Sci Rep 2021; 11:9565. [PMID: 33953276 PMCID: PMC8100105 DOI: 10.1038/s41598-021-88903-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/26/2021] [Indexed: 12/14/2022] Open
Abstract
Enhancement of the late Na+ current (INaL) increases arrhythmia propensity in the heart, while suppression of the current is antiarrhythmic. GS967 is an agent considered as a selective blocker of INaL. In the present study, effects of GS967 on INaL and action potential (AP) morphology were studied in canine ventricular myocytes by using conventional voltage clamp, action potential voltage clamp and sharp microelectrode techniques. The effects of GS967 (1 µM) were compared to those of the class I/B antiarrhythmic compound mexiletine (40 µM). Under conventional voltage clamp conditions, INaL was significantly suppressed by GS967 and mexiletine, causing 80.4 ± 2.2% and 59.1 ± 1.8% reduction of the densities of INaL measured at 50 ms of depolarization, and 79.0 ± 3.1% and 63.3 ± 2.7% reduction of the corresponding current integrals, respectively. Both drugs shifted the voltage dependence of the steady-state inactivation curve of INaL towards negative potentials. GS967 and mexiletine dissected inward INaL profiles under AP voltage clamp conditions having densities, measured at 50% of AP duration (APD), of −0.37 ± 0.07 and −0.28 ± 0.03 A/F, and current integrals of −56.7 ± 9.1 and −46.6 ± 5.5 mC/F, respectively. Drug effects on peak Na+ current (INaP) were assessed by recording the maximum velocity of AP upstroke (V+max) in multicellular preparations. The offset time constant was threefold faster for GS967 than mexiletine (110 ms versus 289 ms), while the onset of the rate-dependent block was slower in the case of GS967. Effects on beat-to-beat variability of APD was studied in isolated myocytes. Beat-to-beat variability was significantly decreased by both GS967 and mexiletine (reduction of 42.1 ± 6.5% and 24.6 ± 12.8%, respectively) while their shortening effect on APD was comparable. It is concluded that the electrophysiological effects of GS967 are similar to those of mexiletine, but with somewhat faster offset kinetics of V+max block. However, since GS967 depressed V+max and INaL at the same concentration, the current view that GS967 represents a new class of drugs that selectively block INaL has to be questioned and it is suggested that GS967 should be classified as a class I/B antiarrhythmic agent.
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Affiliation(s)
- Tamás Hézső
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Muhammad Naveed
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary
| | - Csaba Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Dénes Kiss
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - János Prorok
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary.,MTA-SZTE Research Group for Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - Tamás Árpádffy-Lovas
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary
| | - Richárd Varga
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary
| | - Erika Fujii
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Tanju Mercan
- Department of Biophysics, School of Medicine, Akdeniz University, Antalya, Turkey
| | - Leila Topal
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary
| | - Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Norbert Szentandrássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary.,Department of Basic Medical Sciences, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - János Almássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary.,MTA-SZTE Research Group for Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary.,Division of Sport Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary. .,MTA-SZTE Research Group for Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary. .,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary.
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary. .,Department of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary.
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Dóm tér 12, 6701, Szeged, Hungary.,Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, 4012, Debrecen, Hungary.,Faculty of Pharmacy, University of Debrecen, Debrecen, Hungary
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5
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Nánási PP, Szabó Z, Kistamás K, Horváth B, Virág L, Jost N, Bányász T, Almássy J, Varró A. Implication of frequency-dependent protocols in antiarrhythmic and proarrhythmic drug testing. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 157:76-83. [PMID: 31726065 DOI: 10.1016/j.pbiomolbio.2019.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 10/30/2019] [Accepted: 11/01/2019] [Indexed: 01/20/2023]
Abstract
It has long been known that the electrophysiological effects of many cardioactive drugs strongly depend on the rate dependent frequency. This was recognized first for class I antiarrhythmic agents: their Vmax suppressive effect was attenuated at long cycle lengths. Later many Ca2+ channel blockers were also found to follow such kinetics. The explanation was provided by the modulated and the guarded receptor theories. Regarding the duration of cardiac action potentials (APD) an opposite frequency-dependence was observed, i.e. the drug-induced changes in APD were proportional with the cycle length of stimulation, therefore it was referred as "reverse rate-dependency". The beat-to-beat, or short term variability of APD (SV) has been recognized as an important proarrhythmic mechanism, its magnitude can be used as an arrhythmia predictor. SV is modulated by several cardioactive agents, however, these drugs modify also APD itself. In order to clear the drug-specific effects on SV from the concomitant unspecific APD-change related ones, the term of "relative variability" was introduced. Relative variability is increased by ion channel blockers that decrease the negative feedback control of APD (i.e. blockers of ICa, IKr and IKs) and also by elevation of cytosolic Ca2+. Cardiac arrhythmias are also often categorized according to the characteristic heart rate (tachy- and bradyarrhythmias). Tachycardia is proarrhythmic primarily due to the concomitant Ca2+ overload causing delayed afterdepolarizations. Early afterdepolarizations (EADs) are complications of the bradycardic heart. What is common in the reverse rate-dependent nature of drug action on APD, increased SV and EAD incidence associated with bradycardia.
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Affiliation(s)
- Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary; Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - Zoltán Szabó
- Department of Emergency Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary; Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
| | - Norbert Jost
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary; Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary; MTA-SZTE Research Group for Cardiovascular Pharmacology, Szeged, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Almássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary; Department of Pharmacology and Pharmacotherapy, Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary; MTA-SZTE Research Group for Cardiovascular Pharmacology, Szeged, Hungary.
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6
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Porter B, van Duijvenboden S, Bishop MJ, Orini M, Claridge S, Gould J, Sieniewicz BJ, Sidhu B, Razavi R, Rinaldi CA, Gill JS, Taggart P. Beat-to-Beat Variability of Ventricular Action Potential Duration Oscillates at Low Frequency During Sympathetic Provocation in Humans. Front Physiol 2018; 9:147. [PMID: 29670531 PMCID: PMC5893843 DOI: 10.3389/fphys.2018.00147] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 02/13/2018] [Indexed: 01/22/2023] Open
Abstract
Background: The temporal pattern of ventricular repolarization is of critical importance in arrhythmogenesis. Enhanced beat-to-beat variability (BBV) of ventricular action potential duration (APD) is pro-arrhythmic and is increased during sympathetic provocation. Since sympathetic nerve activity characteristically exhibits burst patterning in the low frequency range, we hypothesized that physiologically enhanced sympathetic activity may not only increase BBV of left ventricular APD but also impose a low frequency oscillation which further increases repolarization instability in humans. Methods and Results: Heart failure patients with cardiac resynchronization therapy defibrillator devices (n = 11) had activation recovery intervals (ARI, surrogate for APD) recorded from left ventricular epicardial electrodes alongside simultaneous non-invasive blood pressure and respiratory recordings. Fixed cycle length was achieved by right ventricular pacing. Recordings took place during resting conditions and following an autonomic stimulus (Valsalva). The variability of ARI and the normalized variability of ARI showed significant increases post Valsalva when compared to control (p = 0.019 and p = 0.032, respectively). The oscillatory behavior was quantified by spectral analysis. Significant increases in low frequency (LF) power (p = 0.002) and normalized LF power (p = 0.019) of ARI were seen following Valsalva. The Valsalva did not induce changes in conduction variability nor the LF oscillatory behavior of conduction. However, increases in the LF power of ARI were accompanied by increases in the LF power of systolic blood pressure (SBP) and the rate of systolic pressure increase (dP/dtmax). Positive correlations were found between LF-SBP and LF-dP/dtmax (rs = 0.933, p < 0.001), LF-ARI and LF-SBP (rs = 0.681, p = 0.001) and between LF-ARI and LF-dP/dtmax (rs = 0.623, p = 0.004). There was a strong positive correlation between the variability of ARI and LF power of ARI (rs = 0.679, p < 0.001). Conclusions: In heart failure patients, physiological sympathetic provocation induced low frequency oscillation (~0.1 Hz) of left ventricular APD with a strong positive correlation between the LF power of APD and the BBV of APD. These findings may be of importance in mechanisms underlying stability/instability of repolarization and arrhythmogenesis in humans.
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Affiliation(s)
- Bradley Porter
- Department of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom
| | | | - Martin J. Bishop
- Department of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom
| | - Michele Orini
- Guy's and St Thomas' Hospital, London, United Kingdom
| | - Simon Claridge
- Department of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom
| | - Justin Gould
- Department of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom
| | - Benjamin J. Sieniewicz
- Department of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom
| | - Baldeep Sidhu
- Department of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom
| | - Reza Razavi
- Department of Imaging Sciences and Biomedical Engineering, Kings College London, London, United Kingdom
| | - Christopher A. Rinaldi
- Department of Cardiovascular Sciences, University College London, London, United Kingdom
| | - Jaswinder S. Gill
- Department of Cardiovascular Sciences, University College London, London, United Kingdom
| | - Peter Taggart
- Guy's and St Thomas' Hospital, London, United Kingdom
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7
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Nánási PP, Magyar J, Varró A, Ördög B. Beat-to-beat variability of cardiac action potential duration: underlying mechanism and clinical implications. Can J Physiol Pharmacol 2017; 95:1230-1235. [PMID: 28746810 DOI: 10.1139/cjpp-2016-0597] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Beat-to-beat variability of cardiac action potential duration (short-term variability, SV) is a common feature of various cardiac preparations, including the human heart. Although it is believed to be one of the best arrhythmia predictors, the underlying mechanisms are not fully understood at present. The magnitude of SV is basically determined by the intensity of cell-to-cell coupling in multicellular preparations and by the duration of the action potential (APD). To compensate for the APD-dependent nature of SV, the concept of relative SV (RSV) has been introduced by normalizing the changes of SV to the concomitant changes in APD. RSV is reduced by ICa, IKr, and IKs while increased by INa, suggesting that ion currents involved in the negative feedback regulation of APD tend to keep RSV at a low level. RSV is also influenced by intracellular calcium concentration and tissue redox potential. The clinical implications of APD variability is discussed in detail.
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Affiliation(s)
- Péter P Nánási
- a Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,b Department of Dental Physiology and Pharmacology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - János Magyar
- a Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - András Varró
- c Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Balázs Ördög
- c Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary
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8
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Porter B, Bishop MJ, Claridge S, Behar J, Sieniewicz BJ, Webb J, Gould J, O'Neill M, Rinaldi CA, Razavi R, Gill JS, Taggart P. Autonomic Modulation in Patients with Heart Failure Increases Beat-to-Beat Variability of Ventricular Action Potential Duration. Front Physiol 2017; 8:328. [PMID: 28611676 PMCID: PMC5447044 DOI: 10.3389/fphys.2017.00328] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 05/05/2017] [Indexed: 12/19/2022] Open
Abstract
Background: Exaggerated beat-to-beat variability of ventricular action potential duration (APD) is linked to arrhythmogenesis. Sympathetic stimulation has been shown to increase QT interval variability, but its effect on ventricular APD in humans has not been determined. Methods and Results: Eleven heart failure patients with implanted bi-ventricular pacing devices had activation–recovery intervals (ARI, surrogate for APD) recorded from LV epicardial electrodes under constant RV pacing. Sympathetic activity was increased using a standard autonomic challenge (Valsalva) and baroreceptor indices were applied to determine changes in sympathetic stimulation. Two Valsalvas were performed for each study and were repeated, both off and on bisoprolol. In addition sympathetic nerve activity (SNA) was measured from skin electrodes on the thorax using a novel validated method. Autonomic modulation significantly increased mean short-term variability in ARI; off bisoprolol mean STV increased from 3.73 ± 1.3 to 5.27 ± 1.04 ms (p = 0.01), on bisoprolol mean STV of ARI increased from 4.15 ± 1.14 to 4.62 ± 1 ms (p = 0.14). Adrenergic indices of the Valsalva demonstrated significantly reduced beta-adrenergic function when on bisoprolol (Δ pressure recovery time, p = 0.04; Δ systolic overshoot in Phase IV, p = 0.05). Corresponding increases in SNA from rest both off (1.4 uV, p < 0.01) and on (0.7 uV, p < 0.01) bisoprolol were also seen. Conclusions: Beat-to-beat variability of ventricular APD increases during brief periods of increased sympathetic activity in patients with heart failure. Bisoprolol reduces, but does not eliminate, these effects. This may be important in the genesis of ventricular arrhythmias in heart failure patients.
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Affiliation(s)
- Bradley Porter
- Department of Imaging Sciences and Biomedical Engineering, Kings College LondonLondon, United Kingdom
| | - Martin J Bishop
- Department of Imaging Sciences and Biomedical Engineering, Kings College LondonLondon, United Kingdom
| | - Simon Claridge
- Department of Imaging Sciences and Biomedical Engineering, Kings College LondonLondon, United Kingdom
| | - Jonathan Behar
- Department of Imaging Sciences and Biomedical Engineering, Kings College LondonLondon, United Kingdom
| | - Benjamin J Sieniewicz
- Department of Imaging Sciences and Biomedical Engineering, Kings College LondonLondon, United Kingdom
| | - Jessica Webb
- Department of Imaging Sciences and Biomedical Engineering, Kings College LondonLondon, United Kingdom
| | - Justin Gould
- Department of Imaging Sciences and Biomedical Engineering, Kings College LondonLondon, United Kingdom
| | - Mark O'Neill
- Cardiology Department, Guy's and St. Thomas' HospitalLondon, United Kingdom
| | | | - Reza Razavi
- Department of Imaging Sciences and Biomedical Engineering, Kings College LondonLondon, United Kingdom
| | - Jaswinder S Gill
- Cardiology Department, Guy's and St. Thomas' HospitalLondon, United Kingdom
| | - Peter Taggart
- Department of Cardiovascular Sciences, University College LondonLondon, United Kingdom
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9
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Feeny A, Tereshchenko LG. Beat-to-beat determinants of the beat-to-beat temporal and spatial variability of repolarization. J Electrocardiol 2016; 49:417-22. [PMID: 26874566 PMCID: PMC4853270 DOI: 10.1016/j.jelectrocard.2016.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Indexed: 11/22/2022]
Abstract
BACKGROUND The goal of this study was to compare the time series predictors of beat-to-beat variability in repolarization in healthy individuals. METHODS Spatial QRS- and T-vector amplitudes, spatial QRS-T, RR' and TT' angles, RR' and QT intervals, and QRS- and T-loop roundness were measured on 453 consecutive sinus beats in 168 healthy subjects (mean age 39.8±15.6years; 50% men; 93% white). Panel time-series regression models were adjusted by age, sex, and race. Appropriate time series of ECG metrics served as predictors and outcomes. RESULTS Increase in T-loop roundness index by 0.1 was associated with 1.1° (95%CI 0.9-2.2; P=0.048) increase in corresponding TT' angle. One unit increase in a respiration index was associated with 4ms (95%CI 0.6-7.0; P=0.021) increase in QT interval. CONCLUSIONS Spatial TT' angle and beat-to-beat variability in T-loop roundness represent intrinsic measures of repolarization variability. QT interval variability characterizes the effect of respiration and heart rate variability.
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Affiliation(s)
- Albert Feeny
- Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Larisa G Tereshchenko
- The Division of Cardiology, Department of Medicine, Johns Hopkins Hospital, Baltimore, MD, USA; The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.
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10
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Hasan MA, Abbott D. A review of beat-to-beat vectorcardiographic (VCG) parameters for analyzing repolarization variability in ECG signals. ACTA ACUST UNITED AC 2016; 61:3-17. [DOI: 10.1515/bmt-2015-0005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 04/17/2015] [Indexed: 11/15/2022]
Abstract
AbstractElevated ventricular repolarization lability is believed to be linked to the risk of ventricular tachycardia/ventricular fibrillation. However, ventricular repolarization is a complex electrical phenomenon, and abnormalities in ventricular repolarization are not completely understood. To evaluate repolarization lability, vectorcardiography (VCG) is an alternative approach where the electrocardiographic (ECG) signal can be considered as possessing both magnitude and direction. Recent research has shown that VCG is advantageous over ECG signal analysis for identification of repolarization abnormality. One of the key reasons is that the VCG approach does not rely on exact identification of the T-wave offset, which improves the reproducibility of the VCG technique. However, beat-to-beat variability in VCG is an emerging area for the investigation of repolarization abnormality though not yet fully realized. Therefore, the purpose of this review is to explore the techniques, findings, and efficacy of beat-to-beat VCG parameters for analyzing repolarization lability, which may have potential utility for further study.
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11
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Kistamás K, Hegyi B, Váczi K, Horváth B, Bányász T, Magyar J, Szentandrássy N, Nánási PP. Oxidative shift in tissue redox potential increases beat-to-beat variability of action potential duration. Can J Physiol Pharmacol 2015; 93:563-8. [DOI: 10.1139/cjpp-2014-0531] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Profound changes in tissue redox potential occur in the heart under conditions of oxidative stress frequently associated with cardiac arrhythmias. Since beat-to-beat variability (short term variability, SV) of action potential duration (APD) is a good indicator of arrhythmia incidence, the aim of this work was to study the influence of redox changes on SV in isolated canine ventricular cardiomyocytes using a conventional microelectrode technique. The redox potential was shifted toward a reduced state using a reductive cocktail (containing dithiothreitol, glutathione, and ascorbic acid) while oxidative changes were initiated by superfusion with H2O2. Redox effects were evaluated as changes in “relative SV” determined by comparing SV changes with the concomitant APD changes. Exposure of myocytes to the reductive cocktail decreased SV significantly without any detectable effect on APD. Application of H2O2 increased both SV and APD, but the enhancement of SV was the greater, so relative SV increased. Longer exposure to H2O2 resulted in the development of early afterdepolarizations accompanied by tremendously increased SV. Pretreatment with the reductive cocktail prevented both elevation in relative SV and the development of afterdepolarizations. The results suggest that the increased beat-to-beat variability during an oxidative stress contributes to the generation of cardiac arrhythmias.
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Affiliation(s)
- Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Bence Hegyi
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Krisztina Váczi
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
- Faculty of Pharmacy, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - János Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
- Division of Sport Physiology, Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Norbert Szentandrássy
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
- Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
| | - Péter P. Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
- Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, H-4012 Debrecen, P.O. Box 22, Hungary
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12
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Waks JW, Soliman EZ, Henrikson CA, Sotoodehnia N, Han L, Agarwal SK, Arking DE, Siscovick DS, Solomon SD, Post WS, Josephson ME, Coresh J, Tereshchenko LG. Beat-to-beat spatiotemporal variability in the T vector is associated with sudden cardiac death in participants without left ventricular hypertrophy: the Atherosclerosis Risk in Communities (ARIC) Study. J Am Heart Assoc 2015; 4:e001357. [PMID: 25600143 PMCID: PMC4330061 DOI: 10.1161/jaha.114.001357] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Background Despite advances in prevention and treatment of cardiovascular disease, sudden cardiac death (SCD) remains a clinical challenge. Risk stratification in the general population is needed. Methods and Results Beat‐to‐beat spatiotemporal variability in the T vector was measured as the mean angle between consecutive T‐wave vectors (mean TT′ angle) on standard 12‐lead ECGs in 14 024 participants in the Atherosclerosis Risk in Communities (ARIC) study. Subjects with left ventricular hypertrophy, atrial arrhythmias, frequent ectopy, ventricular pacing, or QRS duration ≥120 ms were excluded. The mean spatial TT′ angle was 5.21±3.55°. During a median of 14 years of follow‐up, 235 SCDs occurred (1.24 per 1000 person‐years). After adjustment for demographics, coronary heart disease risk factors, and known ECG markers for SCD, mean TT′ angle was independently associated with SCD (hazard ratio 1.089; 95% CI 1.044 to 1.137; P<0.0001). A mean TT′ angle >90th percentile (>9.57°) was associated with a 2‐fold increase in the hazard for SCD (hazard ratio 2.01; 95% CI 1.28 to 3.16; P=0.002). In a subgroup of patients with T‐vector amplitude ≥0.2 mV, the association with SCD was almost twice as strong (hazard ratio 3.92; 95% CI 1.91 to 8.05; P<0.0001). A significant interaction between mean TT′ angle and age was found: TT′ angle was associated with SCD in participants aged <55 years (hazard ratio 1.096; 95% CI 0.043 to 1.152; P<0.0001) but not in participants aged ≥55 years (Pinteraction=0.009). Conclusions In a large, prospective, community‐based cohort of left ventricular hypertrophy–free participants, increased beat‐to‐beat spatiotemporal variability in the T vector, as assessed by increasing TT′ angle, was associated with SCD.
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Affiliation(s)
- Jonathan W Waks
- Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (J.W.W., M.E.J.)
| | - Elsayed Z Soliman
- Epidemiological Cardiology Research Center (EPICARE), Division of Public Health Sciences and Department of Medicine, Cardiology Section, Wake Forest School of Medicine, Winston Salem, NC (E.Z.S.)
| | - Charles A Henrikson
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR (C.A.H., L.G.T.)
| | | | - Lichy Han
- Whitening School of Engineering, Johns Hopkins University, Baltimore, MD (L.H.)
| | - Sunil K Agarwal
- Department of Epidemiology and Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins School of Public Health, Baltimore, MD (S.K.A., J.C.)
| | - Dan E Arking
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (D.E.A.)
| | - David S Siscovick
- University of Washington, Seattle, WA (N.S., D.S.S.) The New York Academy of Medicine, New York, NY (D.S.S.)
| | - Scott D Solomon
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA (S.D.S.)
| | - Wendy S Post
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (W.S.P., L.G.T.)
| | - Mark E Josephson
- Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (J.W.W., M.E.J.)
| | - Josef Coresh
- Department of Epidemiology and Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins School of Public Health, Baltimore, MD (S.K.A., J.C.)
| | - Larisa G Tereshchenko
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR (C.A.H., L.G.T.) Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD (W.S.P., L.G.T.)
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13
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Stojkovic S, Ristl R, Moser FT, Wolzt M, Wojta J, Schmidinger H, Pezawas T. T-Wave Variability for the Prediction of Fast Ventricular Arrhythmias. Circ J 2015; 79:318-24. [DOI: 10.1253/circj.cj-14-1028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Stefan Stojkovic
- Ludwig Boltzmann Cluster for Cardiovascular Research
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna
| | - Robin Ristl
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna
| | - Fabian T. Moser
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna
| | - Michael Wolzt
- Department of Clinical Pharmacology, Medical University of Vienna
| | - Johann Wojta
- Ludwig Boltzmann Cluster for Cardiovascular Research
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna
| | - Herwig Schmidinger
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna
| | - Thomas Pezawas
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna
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14
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Tereshchenko LG. Repolarization Lability Measured by Spatial TT' Angle. COMPUTING IN CARDIOLOGY 2014; 41:181-184. [PMID: 25544586 PMCID: PMC4275103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
AIMS Increased T peaks cloud volume is associated with increased risk of ventricular arrhythmias (VA) in cardiomyopathy (CM) patients. T peaks cloud volume is formed, as a result, of (1) the angle between consecutive T-vectors and (2) temporal variability in T-vector amplitude. This study compares association of these two factors with VA. METHODS Baseline orthogonal ECGs were recorded during 5 min at rest in 414 patients with structural heart disease [mean age 59.4±12.0; 68% whites; 73% men; 45% non-ischemic CM] before implantation of implantable cardioverter-defibrillator (ICD) for primary prevention of sudden cardiac death. The spatial TT' angle between consecutive spatial T vectors was calculated using the definition of the inner product. RESULTS During a median 14 months of follow-up, 61 patients experienced sustained VA with appropriate ICD therapies. In a multivariable Cox regression model after adjustment for age, sex, race, spatial TT' angle was associated with VA (HR 1.03; 95%CI 1.0-1.05; P=0.034). Interaction with CM type was found: TT' angle was strongly associated with polymorphic VT/VF in non-ischemic CM (HR 1.04; 95%CI 1.0-1.05; P=0.033). CONCLUSION Increased spatial TT' angle is associated with increased risk of VA.
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Affiliation(s)
- Larisa G Tereshchenko
- Oregon Health and Science University, Knight Cardiovascular Institute, Portland, Oregon, USA
- Johns Hopkins University School of Medicine, Cardiovascular Division, Baltimore, Maryland, USA
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15
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Contribution of ion currents to beat-to-beat variability of action potential duration in canine ventricular myocytes. Pflugers Arch 2014; 467:1431-1443. [DOI: 10.1007/s00424-014-1581-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/11/2014] [Accepted: 07/14/2014] [Indexed: 12/19/2022]
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16
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Feeny A, Han L, Tereshchenko LG. Repolarization lability measured on 10-second ECG by spatial TT' angle: reproducibility and agreement with QT variability. J Electrocardiol 2014; 47:708-15. [PMID: 25012076 DOI: 10.1016/j.jelectrocard.2014.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Reproducibility of spatial TT' angle on the 10-second ECG and its agreement with QT variability has not been previously studied. METHODS We analyzed 2 randomly selected 10-second segments within 3-minute resting orthogonal ECG in 172 healthy IDEAL study participants (age 38.1±15.2years, 50% male, 94% white). Repolarization lability was measured by the QT variance (QTV), short-term QT variability (STV(QT)), and spatial TT' angle. Bland-Altman analysis was used to assess the agreement between different log-transformed metrics of repolarization lability, and to assess the reproducibility. RESULTS The heart rate showed a very high reproducibility (bias 0.14%, Lin's rho_c=0.99). As expected, noise suppression by averaging improves reproducibility. Agreement between two 10-second LogQTV was poor (bias -0.04; 95% limits of agreement [-1.89; 1.81]), while LogSTV(QT) (0.04 [-1.01; 1.10]), and especially LogTT' angle (-0.009 [-0.84; 0.82]) was better. CONCLUSION TT' angle is a satisfactory reproducible metric of repolarization lability on the 10-second ECG.
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Affiliation(s)
- Albert Feeny
- Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Lichy Han
- Whiting School of Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Larisa G Tereshchenko
- The Division of Cardiology, Department of Medicine, Johns Hopkins Hospital, Baltimore, MD, USA; The Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.
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17
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Homaeinezhad M, ErfanianMoshiri-Nejad M, Naseri H. A correlation analysis-based detection and delineation of ECG characteristic events using template waveforms extracted by ensemble averaging of clustered heart cycles. Comput Biol Med 2014; 44:66-75. [DOI: 10.1016/j.compbiomed.2013.10.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 10/24/2013] [Accepted: 10/26/2013] [Indexed: 11/25/2022]
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18
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Newe A, Ganslandt T. Simplified generation of biomedical 3D surface model data for embedding into 3D portable document format (PDF) files for publication and education. PLoS One 2013; 8:e79004. [PMID: 24260144 PMCID: PMC3829830 DOI: 10.1371/journal.pone.0079004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 09/25/2013] [Indexed: 11/19/2022] Open
Abstract
The usefulness of the 3D Portable Document Format (PDF) for clinical, educational, and research purposes has recently been shown. However, the lack of a simple tool for converting biomedical data into the model data in the necessary Universal 3D (U3D) file format is a drawback for the broad acceptance of this new technology. A new module for the image processing and rapid prototyping framework MeVisLab does not only provide a platform-independent possibility to create surface meshes out of biomedical/DICOM and other data and to export them into U3D – it also lets the user add meta data to these meshes to predefine colors and names that can be processed by a PDF authoring software while generating 3D PDF files. Furthermore, the source code of the respective module is available and well documented so that it can easily be modified for own purposes.
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Affiliation(s)
- Axel Newe
- Chair of Medical Informatics, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
- * E-mail:
| | - Thomas Ganslandt
- Medical Centre for Information and Communication Technology, University Hospital Erlangen, Erlangen, Germany
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19
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Heijman J, Zaza A, Johnson DM, Rudy Y, Peeters RLM, Volders PGA, Westra RL. Determinants of beat-to-beat variability of repolarization duration in the canine ventricular myocyte: a computational analysis. PLoS Comput Biol 2013; 9:e1003202. [PMID: 23990775 PMCID: PMC3749940 DOI: 10.1371/journal.pcbi.1003202] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 06/10/2013] [Indexed: 12/26/2022] Open
Abstract
Beat-to-beat variability of repolarization duration (BVR) is an intrinsic characteristic of cardiac function and a better marker of proarrhythmia than repolarization prolongation alone. The ionic mechanisms underlying baseline BVR in physiological conditions, its rate dependence, and the factors contributing to increased BVR in pathologies remain incompletely understood. Here, we employed computer modeling to provide novel insights into the subcellular mechanisms of BVR under physiological conditions and during simulated drug-induced repolarization prolongation, mimicking long-QT syndromes type 1, 2, and 3. We developed stochastic implementations of 13 major ionic currents and fluxes in a model of canine ventricular-myocyte electrophysiology. Combined stochastic gating of these components resulted in short- and long-term variability, consistent with experimental data from isolated canine ventricular myocytes. The model indicated that the magnitude of stochastic fluctuations is rate dependent due to the rate dependence of action-potential (AP) duration (APD). This process (the “active” component) and the intrinsic nonlinear relationship between membrane current and APD (“intrinsic component”) contribute to the rate dependence of BVR. We identified a major role in physiological BVR for stochastic gating of the persistent Na+ current (INa) and rapidly activating delayed-rectifier K+ current (IKr). Inhibition of IKr or augmentation of INa significantly increased BVR, whereas subsequent β-adrenergic receptor stimulation reduced it, similar to experimental findings in isolated myocytes. In contrast, β-adrenergic stimulation increased BVR in simulated long-QT syndrome type 1. In addition to stochastic channel gating, AP morphology, APD, and beat-to-beat variations in Ca2+ were found to modulate single-cell BVR. Cell-to-cell coupling decreased BVR and this was more pronounced when a model cell with increased BVR was coupled to a model cell with normal BVR. In conclusion, our results provide new insights into the ionic mechanisms underlying BVR and suggest that BVR reflects multiple potentially proarrhythmic parameters, including increased ion-channel stochasticity, prolonged APD, and abnormal Ca2+ handling. Every heartbeat has an electrical recovery (repolarization) interval that varies in duration from beat to beat. Excessive beat-to-beat variability of repolarization duration has been shown to be a risk marker of potentially fatal heart-rhythm disorders, but the contributing subcellular mechanisms remain incompletely understood. Computational models have greatly enhanced our understanding of several basic electrophysiological mechanisms. We developed a detailed computer model of the ventricular myocyte that can simulate beat-to-beat changes in repolarization duration by taking into account stochastic changes in the opening and closing of individual ion channels responsible for all main ion currents. The model accurately reproduced experimental data from isolated myocytes under both physiological and pathological conditions. Using the model, we identified several mechanisms contributing to repolarization variability, including stochastic gating of ion channels, duration and morphology of the repolarization phase, and intracellular calcium handling, thereby providing insights into its basis as a proarrhythmic marker. Our computer model provides a detailed framework to study the dynamics of cardiac electrophysiology and arrhythmias.
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Affiliation(s)
- Jordi Heijman
- Department of Knowledge Engineering, Maastricht University, Maastricht, The Netherlands
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
- Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
| | - Antonio Zaza
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
| | - Daniel M. Johnson
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Yoram Rudy
- Cardiac Bioelectricity and Arrhythmia Center, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Ralf L. M. Peeters
- Department of Knowledge Engineering, Maastricht University, Maastricht, The Netherlands
| | - Paul G. A. Volders
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
- * E-mail: (PGAV); (RLW)
| | - Ronald L. Westra
- Department of Knowledge Engineering, Maastricht University, Maastricht, The Netherlands
- * E-mail: (PGAV); (RLW)
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20
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Hasan MA, Abbott D, Baumert M. Beat-to-beat QT interval variability and T-wave amplitude in patients with myocardial infarction. Physiol Meas 2013; 34:1075-83. [PMID: 23956333 DOI: 10.1088/0967-3334/34/9/1075] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The purpose of this study was to investigate the effects of T-wave amplitude and ECG lead on beat-to-beat QT interval variability (QTV) in patients with myocardial infarction (MI) compared to healthy subjects. Standard resting 12-lead ECGs of 79 MI patients and 69 healthy subjects were investigated. Beat-to-beat QT intervals were measured separately for each lead using a template matching algorithm. In addition, we extracted the beat-to-beat T-wave amplitude in each lead. We computed the standard deviation of beat-to-beat QT intervals as a marker of QTV for both healthy subjects and MI patients. Significant QTV differences were observed between the 12 ECG leads as well as between the groups of healthy subjects and MI patients. Beat-to-beat QTV was significantly higher in MI patients than in healthy subjects for half of the leads. Furthermore, significant T-wave amplitude differences across leads and between groups were observed. A significant inverse relation between beat-to-beat QTV and T-wave amplitude was demonstrated. The group differences in QTV remained significant after co-varying for the T-wave amplitude. In conclusion, the increase in beat-to-beat QTV that has been repeatedly reported in patients with MI is partly due to the lower T-wave amplitudes. However, QTV remains significantly increased in MI patients after covarying for this effect.
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Affiliation(s)
- M A Hasan
- School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, Australia
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21
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Tereshchenko LG. Electrocardiogram as a screening tool in the general population: a strategic review. J Electrocardiol 2013; 46:553-6. [PMID: 23938106 DOI: 10.1016/j.jelectrocard.2013.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Indexed: 01/06/2023]
Abstract
Sudden cardiac death (SCD) is a major public health concern, accounting for 400,000 deaths in the US each year. Clinical and autopsy studies have consistently demonstrated a predominant, common pathophysiology in Western populations, showing that the most common electrophysiological mechanism of SCD is ventricular fibrillation, and the most common pathologic substrate is coronary heart disease (CHD). In about half of SCD cases, death is the first clinical manifestation of CHD. Yet risk factors of SCD early in the natural history of conditions predisposing SCD have not been fully identified, and SCD risk stratification strategy in the general population has not been developed. ECG is an easily available, non-expensive and non-invasive tool, which carries valuable information on electrophysiological properties of the heart. However, traditional analysis of ECG includes very limited assessment of the arrhythmogenic substrate. In this review rationale for development of ECG SCD risk score for screening in the general population is discussed.
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Affiliation(s)
- Larisa G Tereshchenko
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Sur S, Han L, Tereshchenko LG. Comparison of sum absolute QRST integral, and temporal variability in depolarization and repolarization, measured by dynamic vectorcardiography approach, in healthy men and women. PLoS One 2013; 8:e57175. [PMID: 23451181 PMCID: PMC3579786 DOI: 10.1371/journal.pone.0057175] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 01/17/2013] [Indexed: 11/28/2022] Open
Abstract
Background Recently we showed the predictive value of sum absolute QRST integral (SAI QRST) and repolarization lability for risk stratification of sudden cardiac death (SCD) in heart failure patients. The goal of this study was to compare SAI QRST and metrics of depolarization and repolarization variability in healthy men and women. Methods Orthogonal ECGs were recorded at rest for 10 minutes in 160 healthy men and women (mean age 39.6±14.6, 80 men). Mean spatial TT′ angle, and normalized variances of T loop area, of spatial T vector amplitude, of QT interval and Tpeak-Tend area were measured for assessment of repolarization lability. Normalized variances of spatial QRS vector and QRS loop area characterized variability of depolarization. In addition, variability indices (VI) were calculated to adjust for normalized heart rate variance. SAI QRST was measured as the averaged arithmetic sum of areas under the QRST curve. Results Men were characterized by shorter QTc (430.3±21.7 vs. 444.7±22.2 ms; P<0.0001) and larger SAI QRST (282.1±66.7 vs.204.9±58.5 mV*ms; P<0.0001). Repolarization lability negatively correlated with spatial T vector amplitude. Adjusted by normalized heart rate variance, QT variability index was significantly higher in women than in men (−1.54±0.38 vs. −1.70±0.33; P = 0.017). However, in multivariate logistic regression after adjustment for body surface area, QTc, and spatial T vector amplitude, healthy men had 1.5–3 fold higher probability of having larger repolarization lability, as compared to healthy women (T vector amplitude variability index odds ratio 3.88(95%CI 1.4–11.1; P = 0.012). Conclusions Healthy men more likely than women have larger repolarization lability.
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Affiliation(s)
- Sanjoli Sur
- Whiting School of Engineering, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Lichy Han
- Whiting School of Engineering, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Larisa G. Tereshchenko
- The Division of Cardiology, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
- * E-mail:
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Hasan MA, Starc V, Porta A, Abbott D, Baumert M. Improved ECG pre-processing for beat-to-beat QT interval variability measurement. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:2563-2566. [PMID: 24110250 DOI: 10.1109/embc.2013.6610063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The aim of this study was to enhance the ECG pre-processing modalities for beat-to-beat QT interval variability measurement based on template matching. The R-peak detection algorithm has been substituted and an efficient baseline removal algorithm has been implemented in existing computer software. To test performance we used simulated ECG data with fixed QT intervals featuring Gaussian noise, baseline wander and amplitude modulation and two alternative algorithms. We computed the standard deviation of beat-to-beat QT intervals as a marker of QT interval variability (QTV). Significantly a lower beat-to-beat QTV was found in the updated approach compared the original algorithm. In addition, the updated template matching computer software outperformed the previous version in discarding fewer beats. In conclusion, the updated ECG preprocessing algorithm is recommended for more accurate quantification of beat-to-beat QT interval variability.
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Tereshchenko LG, McNitt S, Han L, Berger RD, Zareba W. ECG marker of adverse electrical remodeling post-myocardial infarction predicts outcomes in MADIT II study. PLoS One 2012; 7:e51812. [PMID: 23251630 PMCID: PMC3522579 DOI: 10.1371/journal.pone.0051812] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 11/06/2012] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Post-myocardial infarction (MI) structural remodeling is characterized by left ventricular dilatation, fibrosis, and hypertrophy of the non-infarcted myocardium. OBJECTIVE The goal of our study was to quantify post-MI electrical remodeling by measuring the sum absolute QRST integral (SAI QRST). We hypothesized that adverse electrical remodeling predicts outcomes in MADIT II study participants. METHODS Baseline orthogonal ECGs of 750 MADIT II study participants (448 [59.7%] ICD arm) were analyzed. SAI QRST was measured as the arithmetic sum of absolute QRST integrals over all three orthogonal ECG leads. The primary endpoint was defined as sudden cardiac death (SCD) or sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) with appropriate ICD therapies. All-cause mortality served as a secondary endpoint. RESULTS Adverse electrical remodeling in post-MI patients was characterized by wide QRS, increased magnitudes of spatial QRS and T vectors, J-point deviation, and QTc prolongation. In multivariable Cox regression analysis after adjustment for age, QRS duration, atrial fibrillation, New York Heart Association heart failure class and blood urea nitrogen, SAI QRST predicted SCD/VT/VF (HR 1.33 per 100 mV*ms (95%CI 1.11-1.59); P = 0.002), and all-cause death (HR 1.27 per 100 mV*ms (95%CI 1.03-1.55), P = 0.022) in both arms. No interaction with therapy arm and bundle branch block (BBB) status was found. CONCLUSIONS In MADIT II patients, increased SAI QRST is associated with increased risk of sustained VT/VF with appropriate ICD therapies and all-cause death in both ICD and in conventional medical therapy arms, and in patients with and without BBB. Further studies of SAI QRST are warranted.
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Affiliation(s)
- Larisa G Tereshchenko
- The Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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Beat-to-beat vectorcardiographic analysis of ventricular depolarization and repolarization in myocardial infarction. PLoS One 2012; 7:e49489. [PMID: 23166683 PMCID: PMC3498118 DOI: 10.1371/journal.pone.0049489] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 10/12/2012] [Indexed: 12/20/2022] Open
Abstract
Objectives Increased beat-to-beat variability in the QT interval has been associated with heart disease and mortality. The purpose of this study was to investigate the beat-to-beat spatial and temporal variations of ventricular depolarization and repolarization in vectorcardiogram (VCG) for characterising myocardial infarction (MI) patients. Methods Standard 12-lead ECGs of 84 MI patients (22 f, 63±12 yrs; 62 m, 56±10 yrs) and 69 healthy subjects (17 f, 42±18 yrs; 52 m, 40±13 yrs) were investigated. To extract the beat-to-beat QT intervals, a template-matching algorithm and the singular value decomposition method have been applied to synthesise the ECG data to VCG. Spatial and temporal variations in the QRS complex and T-wave loops were studied by investigating several descriptors (point-to-point distance variability, mean loop length, T-wave morphology dispersion, percentage of loop area, total cosine R-to-T). Results Point-to-point distance variability of QRS and T-loops (0.13±0.04 vs. 0.10±0.04, p< 0.0001 and 0.16±0.07 vs. 0.13±0.06, p< 0.05) were significantly larger in the MI group than in the control group. The average T-wave morphology dispersion was significantly higher in the MI group than in the control group (62°±8° vs. 38°±16°, p< 0.0001). Further, its beat-to-beat variability appeared significantly lower in the MI group than in the control group (12°±5° vs. 15°±6°, p< 0.005). Moreover, the average percentage of the T-loop area was found significantly lower in the MI group than the controls (46±17 vs. 55±15, p< 0.001). Finally, the average and beat-to-beat variability of total cosine R-to-T were not found statistically significant between both groups. Conclusions Beat-to-beat assessment of VCG parameters may have diagnostic attributes that might help in identifying MI patients.
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Johnson DM, Heijman J, Bode EF, Greensmith DJ, van der Linde H, Abi-Gerges N, Eisner DA, Trafford AW, Volders PGA. Diastolic spontaneous calcium release from the sarcoplasmic reticulum increases beat-to-beat variability of repolarization in canine ventricular myocytes after β-adrenergic stimulation. Circ Res 2012; 112:246-56. [PMID: 23149594 DOI: 10.1161/circresaha.112.275735] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Spontaneous Ca(2+) release (SCR) from the sarcoplasmic reticulum can cause delayed afterdepolarizations and triggered activity, contributing to arrhythmogenesis during β-adrenergic stimulation. Excessive beat-to-beat variability of repolarization duration (BVR) is a proarrhythmic marker. Previous research has shown that BVR is increased during intense β-adrenergic stimulation, leading to SCR. OBJECTIVE We aimed to determine ionic mechanisms controlling BVR under these conditions. METHODS AND RESULTS Membrane potentials and cell shortening or Ca(2+) transients were recorded from isolated canine left ventricular myocytes in the presence of isoproterenol. Action-potential (AP) durations after delayed afterdepolarizations were significantly prolonged. Addition of slowly activating delayed rectifier K(+) current (I(Ks)) blockade led to further AP prolongation after SCR, and this strongly correlated with exaggerated BVR. Suppressing SCR via inhibition of ryanodine receptors, Ca(2+)/calmodulin-dependent protein kinase II inhibition, or by using Mg(2+) or flecainide eliminated delayed afterdepolarizations and decreased BVR independent of effects on AP duration. Computational analyses and voltage-clamp experiments measuring L-type Ca(2+) current (I(CaL)) with and without previous SCR indicated that I(CaL) was increased during Ca(2+)-induced Ca(2+) release after SCR, and this contributes to AP prolongation. Prolongation of QT, T(peak)-T(end) intervals, and left ventricular monophasic AP duration of beats after aftercontractions occurred before torsades de pointes in an in vivo dog model of drug-induced long-QT1 syndrome. CONCLUSIONS SCR contributes to increased BVR by interspersed prolongation of AP duration, which is exacerbated during I(Ks) blockade. Attenuation of Ca(2+)-induced Ca(2+) release by SCR underlies AP prolongation via increased I(CaL.) These data provide novel insights into arrhythmogenic mechanisms during β-adrenergic stimulation besides triggered activity and illustrate the importance of I(Ks) function in preventing excessive BVR.
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Affiliation(s)
- Daniel M Johnson
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
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Han L, Cheng A, Sur S, Tomaselli GF, Berger RD, Tereshchenko LG. Complex assessment of the temporal lability of repolarization. Int J Cardiol 2012; 166:543-5. [PMID: 23084544 DOI: 10.1016/j.ijcard.2012.09.189] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 09/25/2012] [Indexed: 11/25/2022]
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Tereshchenko LG, McCabe A, Han L, Sur S, Huang T, Marine JE, Cheng A, Spragg DD, Sinha S, Calkins H, Stein K, Tomaselli GF, Berger RD. Intracardiac J-point elevation before the onset of polymorphic ventricular tachycardia and ventricular fibrillation in patients with an implantable cardioverter-defibrillator. Heart Rhythm 2012; 9:1594-602. [PMID: 22750217 DOI: 10.1016/j.hrthm.2012.06.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Indexed: 01/26/2023]
Abstract
BACKGROUND The clinical importance of the J-point elevation on electrocardiogram is controversial. OBJECTIVE To study intracardiac J-point amplitude before ventricular arrhythmia. METHODS Baseline 12-lead electrocardiogram and far-field right ventricular intracardiac implantable cardioverter-defibrillator electrograms were recorded at rest in 494 patients (mean age 60.4 ± 13.1 years; 360 [72.9%] men) with structural heart disease (278 [56.3%] ischemic cardiomyopathy) who received primary (463 [93.9%] patients) or secondary prevention implantable cardioverter-defibrillator. Ten-second intracardiac far-field electrograms before the onset of arrhythmia were compared with the baseline. The J-point amplitude was measured on the baseline 12-lead surface electrocardiogram and the intracardiac far-field electrogram. The relative J-point amplitude was calculated as the ratio of J-point amplitude to peak-to-peak R-wave. RESULTS The paired t test showed that the relative intracardiac J-point amplitude was significantly higher before polymorphic ventricular tachycardia/ventricular fibrillation (VF) onset (0.28 ± 0.08 vs -0.19 ± 0.39; P = .012) than at baseline. In a mixed-effects logistic regression model, adjusted for multiple episodes per patient, each 10% increase in relative J-point amplitude increased the odds of having ventricular tachycardia/VF by 13% (odds ratio 1.13 [95% confidence interval 1.07-1.19]; P < .0001) and increased the odds of having polymorphic ventricular tachycardia/VF by 27% (odds ratio 1.27 [95% confidence interval 1.11-1.46]; P = .001). CONCLUSIONS The relative intracardiac J-point amplitude is augmented immediately before the onset of polymorphic ventricular tachycardia/VF in patients with structural heart disease.
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Affiliation(s)
- Larisa G Tereshchenko
- Division of Cardiology, Department of Medicine, Johns Hopkins Hospital, 600 N Wolfe St., Baltimore, MD 21287, USA.
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Current World Literature. Curr Opin Support Palliat Care 2011; 5:365-8. [DOI: 10.1097/spc.0b013e32834db0e8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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VERRIER RICHARDL, NIEMINEN TUOMO. T-Wave Variability, the New Microvolt “Buzz” in Arrhythmia Risk Assessment: Any Links to TWA? J Cardiovasc Electrophysiol 2011; 22:806-7. [DOI: 10.1111/j.1540-8167.2011.02026.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lazzara R. Spatial vectorcardiogram to predict risk for sudden arrhythmic death: Phoenix risen from the ashes. Heart Rhythm 2010; 7:1614-5. [DOI: 10.1016/j.hrthm.2010.09.067] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Indexed: 12/01/2022]
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