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Solhjoo S, Haigney MC, Siddharthan T, Koch A, Punjabi NM. Sleep-Disordered Breathing Destabilizes Ventricular Repolarization. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2023.02.10.23285789. [PMID: 36824787 PMCID: PMC9949208 DOI: 10.1101/2023.02.10.23285789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Rationale Sleep-disordered breathing (SDB) increases the risk of cardiac arrhythmias and sudden cardiac death. Objectives To characterize the associations between SDB, intermittent hypoxemia, and the beat-to-beat QT variability index (QTVI), a measure of ventricular repolarization lability associated with a higher risk for cardiac arrhythmias, sudden cardiac death, and mortality. Methods Three distinct cohorts were used for the current study. The first cohort, used for cross-sectional analysis, was a matched sample of 122 participants with and without severe SDB. The second cohort, used for longitudinal analysis, consisted of a matched sample of 52 participants with and without incident SDB. The cross-sectional and longitudinal cohorts were selected from the Sleep Heart Health Study participants. The third cohort comprised 19 healthy adults exposed to acute intermittent hypoxia and ambient air on two separate days. Electrocardiographic measures were calculated from one-lead electrocardiograms. Results Compared to those without SDB, participants with severe SDB had greater QTVI (-1.19 in participants with severe SDB vs. -1.43 in participants without SDB, P = 0.027), heart rate (68.34 vs. 64.92 beats/minute; P = 0.028), and hypoxemia burden during sleep as assessed by the total sleep time with oxygen saturation less than 90% (TST90; 11.39% vs. 1.32%, P < 0.001). TST90, but not the frequency of arousals, was a predictor of QTVI. QTVI during sleep was predictive of all-cause mortality. With incident SDB, mean QTVI increased from -1.23 to -0.86 over 5 years (P = 0.017). Finally, exposing healthy adults to acute intermittent hypoxia for four hours progressively increased QTVI (from -1.85 at baseline to -1.64 after four hours of intermittent hypoxia; P = 0.016). Conclusions Prevalent and incident SDB are associated with ventricular repolarization instability, which predisposes to ventricular arrhythmias and sudden cardiac death. Intermittent hypoxemia destabilizes ventricular repolarization and may contribute to increased mortality in SDB.
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Affiliation(s)
- Soroosh Solhjoo
- Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F. Edward Hébert School of Medicine, Bethesda, Maryland, USA
| | - Mark C. Haigney
- F. Edward Hébert School of Medicine, Bethesda, Maryland, USA
- Military Cardiovascular Outcomes Research (MiCOR), Bethesda, Maryland, USA
| | | | - Abigail Koch
- University of Miami Miller School of Medicine, Miami, Florida, USA
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The role of β-adrenergic stimulation in QT interval adaptation to heart rate during stress test. PLoS One 2023; 18:e0280901. [PMID: 36701349 PMCID: PMC9879473 DOI: 10.1371/journal.pone.0280901] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 01/10/2023] [Indexed: 01/27/2023] Open
Abstract
The adaptation lag of the QT interval after heart rate (HR) has been proposed as an arrhythmic risk marker. Most studies have quantified the QT adaptation lag in response to abrupt, step-like changes in HR induced by atrial pacing, in response to tilt test or during ambulatory recordings. Recent studies have introduced novel methods to quantify the QT adaptation lag to gradual, ramp-like HR changes in stress tests by evaluating the differences between the measured QT series and an estimated, memoryless QT series obtained from the instantaneous HR. These studies have observed the QT adaptation lag to progressively reduce when approaching the stress peak, with the underlying mechanisms being still unclear. This study analyzes the contribution of β-adrenergic stimulation to QT interval rate adaptation in response to gradual, ramp-like HR changes. We first quantify the QT adaptation lag in Coronary Artery Disease (CAD) patients undergoing stress test. To uncover the involved mechanisms, we use biophysically detailed computational models coupling descriptions of human ventricular electrophysiology and β-adrenergic signaling, from which we simulate ventricular action potentials and ECG signals. We characterize the adaptation of the simulated QT interval in response to the HR time series measured from each of the analyzed CAD patients. We show that, when the simulated ventricular tissue is subjected to a time-varying β-adrenergic stimulation pattern, with higher stimulation levels close to the stress peak, the simulated QT interval presents adaptation lags during exercise that are more similar to those measured from the patients than when subjected to constant β-adrenergic stimulation. During stress test recovery, constant and time-varying β-adrenergic stimulation patterns render similar adaptation lags, which are generally shorter than during exercise, in agreement with results from the patients. In conclusion, our findings support the role of time-varying β-adrenergic stimulation in contributing to QT interval adaptation to gradually increasing HR changes as those seen during the exercise phase of a stress test.
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El-Hamad F, Javorka M, Czippelova B, Krohova J, Turianikova Z, Porta A, Baumert M. Repolarization variability independent of heart rate during sympathetic activation elicited by head-up tilt. Med Biol Eng Comput 2019; 57:1753-1762. [PMID: 31187400 DOI: 10.1007/s11517-019-01998-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 05/22/2019] [Indexed: 12/22/2022]
Abstract
The fraction of repolarization variability independent of RR interval variability is of clinical interest. It has been linked to direct autonomic nervous system (ANS) regulation of the ventricles in healthy subjects and seems to reflect the instability of the ventricular repolarization process in heart disease. In this study, we sought to identify repolarization measures that best reflect the sympathetic influences on the ventricles independent of the RR interval. ECG was recorded in 46 young subjects during supine and then following 45 degrees head-up tilt. RR intervals and five repolarization features (QTend, QTpeak, RTend, RTpeak, and TpTe) were extracted from the ECG recordings. Repolarization variability was separated into RR-dependent and RR-independent variability using parametric spectral analysis. Results show that LF power of TpTe is independent of RR in both supine and tilt, while the LF power of QTend and RTend independent of RR and respiration increases following tilt. We conclude that TpTe is independent of RR and is highly affected by respiration. QTend and RTend LF power might reflect the sympathetic influences on the ventricles elicited by tilt. Graphical abstract.
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Affiliation(s)
- Fatima El-Hamad
- School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Michal Javorka
- Department of Physiology and Biomedical Center BioMed Martin, Jessenius Faculty of Medicine, Comenius University, Mala Hora 4C, 036 01, Martin, Slovakia
| | - Barbora Czippelova
- Department of Physiology and Biomedical Center BioMed Martin, Jessenius Faculty of Medicine, Comenius University, Mala Hora 4C, 036 01, Martin, Slovakia
| | - Jana Krohova
- Department of Physiology and Biomedical Center BioMed Martin, Jessenius Faculty of Medicine, Comenius University, Mala Hora 4C, 036 01, Martin, Slovakia
| | - Zuzana Turianikova
- Department of Physiology and Biomedical Center BioMed Martin, Jessenius Faculty of Medicine, Comenius University, Mala Hora 4C, 036 01, Martin, Slovakia
| | - Alberto Porta
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.,Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Mathias Baumert
- School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA, 5005, Australia.
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Hasan MA, Abbott D, Baumert M, Krishnan S. Increased beat-to-beat T-wave variability in myocardial infarction patients. ACTA ACUST UNITED AC 2018; 63:123-130. [PMID: 28002025 DOI: 10.1515/bmt-2015-0186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 11/15/2016] [Indexed: 11/15/2022]
Abstract
The purpose of this study was to investigate the beat-to-beat variability of T-waves (TWV) and to assess the diagnostic capabilities of T-wave-based features for myocardial infarction (MI). A total of 148 recordings of standard 12-lead electrocardiograms (ECGs) from 79 MI patients (22 females, mean age 63±12 years; 57 males, mean age 57±10 years) and 69 recordings from healthy subjects (HS) (17 females, 42±18 years; 52 males, 40±13 years) were studied. For the quantification of beat-to-beat QT intervals in ECG signal, a template-matching algorithm was applied. To study the T-waves beat-to-beat, we measured the angle between T-wave max and T-wave end with respect to Q-wave (∠α) and T-wave amplitudes. We computed the standard deviation (SD) of beat-to-beat T-wave features and QT intervals as markers of variability in T-waves and QT intervals, respectively, for both patients and HS. Moreover, we investigated the differences in the studied features based on gender and age for both groups. Significantly increased TWV and QT interval variability (QTV) were found in MI patients compared to HS (p<0.05). No significant differences were observed based on gender or age. TWV may have some diagnostic attributes that may facilitate identifying patients with MI. In addition, the proposed beat-to-beat angle variability was found to be independent of heart rate variations. Moreover, the proposed feature seems to have higher sensitivity than previously reported feature (QT interval and T-wave amplitude) variability for identifying patients with MI.
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Affiliation(s)
- Muhammad A Hasan
- Department of Electrical and Computer Engineering, Ryerson University, Toronto, Canada
- Department of Electrical and Electronics Engineering, The University of Adelaide, Adelaide, Australia
| | - Derek Abbott
- Department of Electrical and Electronics Engineering, The University of Adelaide, Adelaide, Australia
| | - Mathias Baumert
- Department of Electrical and Electronics Engineering, The University of Adelaide, Adelaide, Australia
| | - Sridhar Krishnan
- Department of Electrical and Computer Engineering, Ryerson University, Toronto, Canada
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Orini M, Pueyo E, Laguna P, Bailon R. A Time-Varying Nonparametric Methodology for Assessing Changes in QT Variability Unrelated to Heart Rate Variability. IEEE Trans Biomed Eng 2017; 65:1443-1451. [PMID: 28991727 DOI: 10.1109/tbme.2017.2758925] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To propose and test a novel methodology to measure changes in QT interval variability (QTV) unrelated to RR interval variability (RRV) in nonstationary conditions. METHODS Time-frequency coherent and residual spectra representing QTV related (QTVrRRV) and unrelated (QTVuRRV) to RRV, respectively, are estimated using time-frequency Cohen's class distributions. The proposed approach decomposes the nonstationary output spectrum of any two-input one-output model with uncorrelated inputs into two spectra representing the information related and unrelated to one of the two inputs, respectively. An algorithm to correct for the bias of the time-frequency coherence function between QTV and RRV is proposed to provide accurate estimates of both QTVuRRV and QTVrRRV. Two simulation studies were conducted to assess the methodology in challenging nonstationary conditions and data recorded during head-up tilt in 16 healthy volunteers were analyzed. RESULTS In the simulation studies, QTVuRRV changes were tracked with only a minor delay due to the filtering necessary to estimate the nonstationary spectra. The correlation coefficient between theoretical and estimated patterns was even for extremely noisy recordings (signal to noise ratio (SNR) in QTV dB). During head-up tilt, QTVrRRV explained the largest proportion of QTV, whereas QTVuRRV showed higher relative increase than QTV or QTVrRRV in all spectral bands ( for most pairwise comparisons). CONCLUSION The proposed approach accurately tracks changes in QTVuRRV. Head-up tilt induced a slightly greater increase in QTVuRRV than in QTVrRRV. SIGNIFICANCE The proposed index QTVuRRV may represent an indirect measure of intrinsic ventricular repolarization variability, a marker of cardiac instability associated with sympathetic ventricular modulation and sudden cardiac death.
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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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Effect of Loss of Heart Rate Variability on T-Wave Heterogeneity and QT Variability in Heart Failure Patients: Implications in Ventricular Arrhythmogenesis. Cardiovasc Eng Technol 2017; 8:219-228. [DOI: 10.1007/s13239-017-0299-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 02/25/2017] [Indexed: 11/25/2022]
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Yaghini Bonabi S, El-Hamad F, Müller A, Dommasch M, Steger A, Schmidt G, Baumert M. Recording duration and short-term reproducibility of heart rate and QT interval variability in patients with myocardial infarction. Physiol Meas 2016; 37:1925-1933. [PMID: 27681306 DOI: 10.1088/0967-3334/37/11/1925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Beat-to-beat variability of the QT interval (QTV) measured on surface ECG has emerged as a potential marker for ventricular repolarization instability and has been used along with heart rate variability (HRV) to predict arrhythmic risk. Since measurement modalities of QTV have not been standardized, the objective of this study was to investigate the effect of ECG recording duration on QTV as well as HRV. Using a database of 30 min ECG recorded from 500 patients with acute myocardial infraction during rest, we extracted RR and QT interval time series and estimated different HRV and QTV metrics over windows of varying length. Analysis of variance (ANOVA) and intra-class correlation analyses were computed to investigate the effect of recording length on consistency and short-term reproducibility of HRV and QTV variables. Good consistency (non-significant ANOVA results) and short-term reproducibility (intra-class correlation coefficients >0.8) were demonstrated for all but standard deviation based metrics when at least 200 beats were included in the estimation. In conclusion, QTV can be quantified from resting ECG with good short-term consistency and reproducibility that is comparable to that of HRV.
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Affiliation(s)
- Safa Yaghini Bonabi
- School of Electrical and Electronic Engineering, The University of Adelaide, SA 5005, Australia
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9
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Baumert M, Porta A, Vos MA, Malik M, Couderc JP, Laguna P, Piccirillo G, Smith GL, Tereshchenko LG, Volders PGA. QT interval variability in body surface ECG: measurement, physiological basis, and clinical value: position statement and consensus guidance endorsed by the European Heart Rhythm Association jointly with the ESC Working Group on Cardiac Cellular Electrophysiology. Europace 2016; 18:925-44. [PMID: 26823389 PMCID: PMC4905605 DOI: 10.1093/europace/euv405] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 11/05/2015] [Indexed: 12/20/2022] Open
Abstract
This consensus guideline discusses the electrocardiographic phenomenon of beat-to-beat QT interval variability (QTV) on surface electrocardiograms. The text covers measurement principles, physiological basis, and clinical value of QTV. Technical considerations include QT interval measurement and the relation between QTV and heart rate variability. Research frontiers of QTV include understanding of QTV physiology, systematic evaluation of the link between QTV and direct measures of neural activity, modelling of the QTV dependence on the variability of other physiological variables, distinction between QTV and general T wave shape variability, and assessing of the QTV utility for guiding therapy. Increased QTV appears to be a risk marker of arrhythmic and cardiovascular death. It remains to be established whether it can guide therapy alone or in combination with other risk factors. QT interval variability has a possible role in non-invasive assessment of tonic sympathetic activity.
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Affiliation(s)
- Mathias Baumert
- School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA, Australia
| | - Alberto Porta
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy Department of Cardiothoracic, Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy
| | - Marc A Vos
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marek Malik
- St Paul's Cardiac Electrophysiology, University of London, and National Heart and Lung Institute, Imperial College, Dovehouse Street, London SW3 6LY, UK
| | - Jean-Philippe Couderc
- Heart Research Follow-Up Program, University of Rochester Medical Center, Rochester, NY, USA
| | - Pablo Laguna
- Zaragoza University and CIBER-BBN, Zaragoza, Spain
| | - Gianfranco Piccirillo
- Dipartimento di Scienze Cardiovascolari, Respiratorie, Nefrologiche, Anestesiologiche e Geriatriche, Università 'La Sapienza' Rome, Rome, Italy
| | - Godfrey L Smith
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Larisa G Tereshchenko
- Oregon Health and Science University, Knight Cardiovascular Institute, Portland, OR, USA
| | - Paul G A Volders
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands
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Kapa S, DeSimone CV, Asirvatham SJ. Innervation of the heart: An invisible grid within a black box. Trends Cardiovasc Med 2016; 26:245-57. [PMID: 26254961 PMCID: PMC4706824 DOI: 10.1016/j.tcm.2015.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 06/30/2015] [Accepted: 07/02/2015] [Indexed: 02/07/2023]
Abstract
Autonomic control of cardiovascular function is mediated by a complex interplay between central, peripheral, and innate cardiac components. This interplay is what mediates the normal cardiovascular response to physiologic and pathologic stressors, including blood pressure, cardiac contractile function, and arrhythmias. However, in order to understand how modern therapies directly affecting autonomic function may be harnessed to treat various cardiovascular disease states requires an intimate understanding of anatomic and physiologic features of the innervation of the heart. Thus, in this review, we focus on defining features of the central, peripheral, and cardiac components of cardiac innervation, how each component may contribute to dysregulation of normal cardiac function in various disease states, and how modulation of these components may offer therapeutic options for these diseases.
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Affiliation(s)
- Suraj Kapa
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | - Christopher V DeSimone
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | - Samuel J Asirvatham
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN; Division of Pediatric Cardiology, Department of Pediatrics and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN.
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Baumert M, Schmidt M, Zaunseder S, Porta A. Effects of ECG sampling rate on QT interval variability measurement. Biomed Signal Process Control 2016. [DOI: 10.1016/j.bspc.2015.11.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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12
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Meo M, Meste O, Signore S, Sorrentino A, Cannata A, Zhou Y, Matsuda A, Luciani M, Kannappan R, Goichberg P, Leri A, Anversa P, Rota M. Reduction in Kv Current Enhances the Temporal Dispersion of the Action Potential in Diabetic Myocytes: Insights From a Novel Repolarization Algorithm. J Am Heart Assoc 2016; 5:e003078. [PMID: 26896476 PMCID: PMC4802457 DOI: 10.1161/jaha.115.003078] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 01/02/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND Diabetes is associated with prolongation of the QT interval of the electrocardiogram and enhanced dispersion of ventricular repolarization, factors that, together with atherosclerosis and myocardial ischemia, may promote the occurrence of electrical disorders. Thus, we tested the possibility that alterations in transmembrane ionic currents reduce the repolarization reserve of myocytes, leading to action potential (AP) prolongation and enhanced beat-to-beat variability of repolarization. METHODS AND RESULTS Diabetes was induced in mice with streptozotocin (STZ), and effects of hyperglycemia on electrical properties of whole heart and myocytes were studied with respect to an untreated control group (Ctrl) using electrocardiographic recordings in vivo, ex vivo perfused hearts, and single-cell patch-clamp analysis. Additionally, a newly developed algorithm was introduced to obtain detailed information of the impact of high glucose on AP profile. Compared to Ctrl, hyperglycemia in STZ-treated animals was coupled with prolongation of the QT interval, enhanced temporal dispersion of electrical recovery, and susceptibility to ventricular arrhythmias, defects observed, in part, in the Akita mutant mouse model of type I diabetes. AP was prolonged and beat-to-beat variability of repolarization was enhanced in diabetic myocytes, with respect to Ctrl cells. Density of Kv K(+) and L-type Ca(2+) currents were decreased in STZ myocytes, in comparison to cells from normoglycemic mice. Pharmacological reduction of Kv currents in Ctrl cells lengthened AP duration and increased temporal dispersion of repolarization, reiterating features identified in diabetic myocytes. CONCLUSIONS Reductions in the repolarizing K(+) currents may contribute to electrical disturbances of the diabetic heart.
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Affiliation(s)
- Marianna Meo
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Olivier Meste
- Laboratoire d'Informatique, Signaux et Systèmes de Sophia Antipolis (I3S), Université Nice Sophia Antipolis, CNRS, Nice, France
| | - Sergio Signore
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Andrea Sorrentino
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Antonio Cannata
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Yu Zhou
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Alex Matsuda
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA Fondazione Cardiocentro Ticino, University of Zurich, Lugano, Switzerland
| | - Marco Luciani
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Ramaswamy Kannappan
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Polina Goichberg
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Annarosa Leri
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA Fondazione Cardiocentro Ticino, University of Zurich, Lugano, Switzerland
| | - Piero Anversa
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA Fondazione Cardiocentro Ticino, University of Zurich, Lugano, Switzerland
| | - Marcello Rota
- Division of Cardiovascular Medicine, Departments of Anesthesia and Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA Department of Physiology, New York Medical College, Valhalla, NY
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El-Hamad F, Lambert E, Abbott D, Baumert M. Relation between QT interval variability and muscle sympathetic nerve activity in normal subjects. Am J Physiol Heart Circ Physiol 2015; 309:H1218-24. [DOI: 10.1152/ajpheart.00230.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 08/12/2015] [Indexed: 01/06/2023]
Abstract
Beat-to-beat variability of the QT interval (QTV) is sought to provide an indirect noninvasive measure of sympathetic nerve activity, but a formal quantification of this relationship has not been provided. In this study we used power contribution analysis to study the relationship between QTV and muscle sympathetic nerve activity (MSNA). ECG and MSNA were recorded in 10 healthy subjects in the supine position and after 40° head-up tilt. Power spectrum analysis was performed using a linear autoregressive model with two external inputs: heart period (RR interval) variability (RRV) and MSNA. Total and low-frequency power of QTV was decomposed into contributions by RRV, MSNA, and sources independent of RRV and MSNA. Results show that the percentage of MSNA power contribution to QT is very small and does not change with tilt. RRV power contribution to QT power is notable and decreases with tilt, while the greatest percentage of QTV is independent of RRV and MSNA in the supine position and after 40° head-up tilt. In conclusion, beat-to-beat QTV in normal subjects does not appear to be significantly affected by the rhythmic modulations in MSNA following low to moderate orthostatic stimulation. Therefore, MSNA oscillations may not represent a useful surrogate for cardiac sympathetic nerve activity at moderate levels of activation, or, alternatively, sympathetic influences on QTV are complex and not quantifiable with linear shift-invariant autoregressive models.
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Affiliation(s)
- Fatima El-Hamad
- School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, South Australia, Australia; and
| | - Elisabeth Lambert
- Human Neurotransmitter Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Derek Abbott
- School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, South Australia, Australia; and
| | - Mathias Baumert
- School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, South Australia, Australia; and
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14
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Valencia JF, Vallverdu M, Rivero I, Voss A, de Luna AB, Porta A, Caminal P. Symbolic dynamics to discriminate healthy and ischaemic dilated cardiomyopathy populations: an application to the variability of heart period and QT interval. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2014.0092. [PMID: 25548268 PMCID: PMC4281865 DOI: 10.1098/rsta.2014.0092] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Myocardial ischaemia is hypothesized to stimulate the cardiac sympathetic excitatory afferents and, therefore, the spontaneous changes of heart period (approximated as the RR interval), and the QT interval in ischaemic dilated cardiomyopathy (IDC) patients might reflect this sympathetic activation. Symbolic analysis is a nonlinear and powerful tool for the extraction and classification of patterns in time-series analysis, which implies a transformation of the original series into symbols and the construction of patterns with the symbols. The aim of this work was to investigate whether symbolic transformations of RR and QT cardiac series can provide a better separation between IDC patients and healthy control (HC) subjects compared with traditional linear measures. The variability of these cardiac series was studied during daytime and night-time periods and also during the complete 24 h recording over windows of short data sequences of approximately 5 min. The IDC group was characterized by an increase in the occurrence rate of patterns without variations (0 V%) and a reduction in the occurrence rate of patterns with one variation (1 V%) and two variations (2 V%). Concerning the RR variability during the daytime, the highest number of patterns had 0 V%, whereas the rates of 1 V% and 2 V% were lower. During the night, 1 V% and 2 V% increased at the expense of diminishing 0 V%. Patterns with and without variations between consecutive symbols were able to increase the separation between the IDC and HC groups, allowing accuracies higher than 80%. With regard to entropy measures, an increase in RR regularity was associated with cardiac disease described by accuracy >70% in the RR series and by accuracy >60% in the QTc series. These results could be associated with an increase in the sympathetic tone in IDC patients.
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Affiliation(s)
- José Fernando Valencia
- Department of Electronic Engineering, Universidad de San Buenaventura, Cali, Colombia Department of Automatic Control, Center for Biomedical Engineering Research, Universitat Politècnica de Catalunya, CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain
| | - Montserrat Vallverdu
- Department of Automatic Control, Center for Biomedical Engineering Research, Universitat Politècnica de Catalunya, CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain
| | - Isidre Rivero
- Department of Automatic Control, Center for Biomedical Engineering Research, Universitat Politècnica de Catalunya, CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain
| | - Andreas Voss
- Department of Medical Engineering, University of Applied Sciences, Jena, Germany
| | | | - Alberto Porta
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy IRCCS Galeazzi Orthopedic Institute, Milan, Italy
| | - Pere Caminal
- Department of Automatic Control, Center for Biomedical Engineering Research, Universitat Politècnica de Catalunya, CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain
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15
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Entropy Analysis of RR and QT Interval Variability during Orthostatic and Mental Stress in Healthy Subjects. ENTROPY 2014. [DOI: 10.3390/e16126384] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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