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Takeuchi Y, Omeki Y, Horio K, Nishio M, Nagata R, Oikawa S, Mizutani Y, Nagatani A, Funamoto Y, Uchida H, Fujino M, Eryu Y, Boda H, Miyata M, Hata T. Relationship between QT and JT peak interval variability in prepubertal children. Ann Noninvasive Electrocardiol 2017; 22. [PMID: 28211121 DOI: 10.1111/anec.12444] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 12/28/2016] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND The QT variability index (QTVI) is a noninvasive index of repolarization lability that has been applied to subjects with cardiovascular disease. QTVI provides a ratio of normalized QT variability to normalized heart rate variability, and therefore includes an assessment of autonomic nervous activity. However, measurement of QT time is particularly difficult in children, who exhibit physiologically high heart rates compared with adults. In this study, we developed a set of standard values of J-point to Tpeak interval (JTp) for infants by age, and assessed the correlation of QTVI with the JTp variability index (JTpVI). METHODS Subjects included 623 infants and children (0-7 years of age) without heart disease and 57 healthy university students. All subjects were divided into three groups by age. QTVI and JTpVI were calculated based on an electrocardiogram, and age-specific standard values, a gender-specific classification, and a standard growth curve were constructed. RESULTS JTpVI markedly decreased in infancy and slowly decreased thereafter, reaching adult values by school age. There was also a strong correlation of JTpVI with QTVI (r = .856). CONCLUSIONS JTp can be used to evaluate the variability of the repolarization time in healthy infants, and may be useful for detection of early repolarization abnormalities.
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Affiliation(s)
- Yuka Takeuchi
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Yumi Omeki
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Kayo Horio
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Miki Nishio
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Rina Nagata
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Shota Oikawa
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Yuri Mizutani
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan
| | - Arisa Nagatani
- Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Yuri Funamoto
- Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Hidetoshi Uchida
- Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Masayuki Fujino
- Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Yoshihiko Eryu
- Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Hiroko Boda
- Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Masafumi Miyata
- Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan
| | - Tadayoshi Hata
- Graduate School of Health Sciences, Fujita Health University, Toyoake, Japan.,Department of Pediatrics, School of Medicine, Fujita Health University, Toyoake, Japan
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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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Interleukin-1β gene variants are associated with QTc interval prolongation following cardiac surgery: a prospective observational study. Can J Anaesth 2016; 63:397-410. [PMID: 26858093 DOI: 10.1007/s12630-015-0576-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 10/13/2015] [Accepted: 12/21/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND We characterized cardiac surgery-induced dynamic changes of the corrected QT (QTc) interval and tested the hypothesis that genetic factors are associated with perioperative QTc prolongation independent of clinical and procedural factors. METHODS All study subjects were ascertained from a prospective study of patients who underwent elective cardiac surgery during August 1999 to April 2002. We defined a prolonged QTc interval as > 440 msec, measured from 24-hr pre- and postoperative 12-lead electrocardiograms. The association of 37 single nucleotide polymorphisms (SNPs) in 21 candidate genes -involved in modulating arrhythmia susceptibility pathways with postoperative QTc changes- was investigated in a two-stage design with a stage I cohort (n = 497) nested within a stage II cohort (n = 957). Empirical P values (Pemp) were obtained by permutation tests with 10,000 repeats. RESULTS After adjusting for clinical and procedural risk factors, we selected four SNPs (P value range, 0.03-0.1) in stage I, which we then tested in the stage II cohort. Two functional SNPs in the pro-inflammatory cytokine interleukin-1β (IL1β), rs1143633 (odds ratio [OR], 0.71; 95% confidence interval [CI], 0.53 to 0.95; Pemp = 0.02) and rs16944 (OR, 1.31; 95% CI, 1.01 to 1.70; Pemp = 0.04), remained independent predictors of postoperative QTc prolongation. The ability of a clinico-genetic model incorporating the two IL1B polymorphisms to classify patients at risk for developing prolonged postoperative QTc was superior to a clinical model alone, with a net reclassification improvement of 0.308 (P = 0.0003) and an integrated discrimination improvement of 0.02 (P = 0.000024). CONCLUSION The results suggest a contribution of IL1β in modulating susceptibility to postoperative QTc prolongation after cardiac surgery.
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Kaya E, Karabacak K, Kadan M, Gurses KM, Kocyigit D, Doganci S, Yildirim V, Demirkilic U. Preoperative frontal QRS-T angle is an independent correlate of hospital length of stay and predictor of haemodynamic support requirement following off-pump coronary artery bypass graft surgery. Interact Cardiovasc Thorac Surg 2015; 21:96-101. [PMID: 25911679 DOI: 10.1093/icvts/ivv084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 02/17/2015] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES With the adoption of novel operative techniques and aggressive care protocols that facilitate earlier extubation and mobilization of patients, postoperative length of stay (LOS) following coronary artery bypass graft surgery (CABG) has declined. However, there is paucity of information regarding preoperative electrocardiographic predictors of LOS following CABG. In this study, we investigated whether frontal QRS-T angle, which is an abnormal repolarization marker in prediction of various cardiovascular events, was an independent correlate of postoperative hospital LOS for off-pump CABG. Furthermore, we evaluated independent predictors of vasopressor agent/intra-aortic balloon pump (IABP) support requirement following off-pump CABG. METHODS In this observational study, 78 patients with stable angina, who were scheduled for elective coronary artery bypass surgery following diagnosis of obstructive coronary artery disease by conventional angiography, were enrolled. RESULTS Left ventricular ejection fraction (LVEF) was significantly lower and vasopressor agent/IABP support requirement and incidence of sustained atrial or ventricular arrhythmias was higher in patients with wide QRS-T angle (P < 0.05). Postoperative hospital LOS was also longer in this group. From the preoperative characteristics, wide frontal QRS-T angle was found to be an independent correlate of postoperative hospital LOS (B ± SD: 11.97 ± 0.62, P ≤ 0.01). Wide frontal QRS-T angle was also found to be an independent predictor of vasopressor agent/IABP support requirement postoperatively (OR: 7.87, P ≤ 0.01). CONCLUSIONS Prediction of the hospital LOS and patient outcome following CABG is of great importance. Being easily obtainable via standard 12-lead electrocardiogram and its low cost may make frontal QRS-T angle a beneficial marker for reducing both patient-based morbidity and economic burden.
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Affiliation(s)
- Erkan Kaya
- Department of Cardiovascular Surgery, Gulhane Military Medical Academy, Ankara, Turkey
| | - Kubilay Karabacak
- Department of Cardiovascular Surgery, Gulhane Military Medical Academy, Ankara, Turkey
| | - Murat Kadan
- Department of Cardiovascular Surgery, Gulhane Military Medical Academy, Ankara, Turkey
| | - Kadri Murat Gurses
- Department of Cardiology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Duygu Kocyigit
- Department of Cardiology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Suat Doganci
- Department of Cardiovascular Surgery, Gulhane Military Medical Academy, Ankara, Turkey
| | - Vedat Yildirim
- Department of Anaesthesiology and Reanimation, Gulhane Military Medical Academy, Ankara, Turkey
| | - Ufuk Demirkilic
- Department of Cardiovascular Surgery, Gulhane Military Medical Academy, Ankara, Turkey
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Tereshchenko LG, Berger RD. Towards a better understanding of QT interval variability. Ther Adv Drug Saf 2014; 2:245-51. [PMID: 25083216 DOI: 10.1177/2042098611421209] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) Guideline E14 recommends 'Thorough QT Study' as a standard assessment of drug-induced QT interval prolongation. At the same time, the value of drug-induced QTc prolongation as a surrogate marker for risk of life-threatening polymorphic ventricular tachycardia known as torsades des pointes remains controversial. Beat-to-beat variability of QT interval was recently proposed as an alternative metric. The following review addresses mechanisms of beat-to-beat QT variability, methods of QT interval variability measurements, and its prognostic value in clinical studies.
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Affiliation(s)
- Larisa G Tereshchenko
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ronald D Berger
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Carnegie 592, 600 N. Wolfe St., Baltimore, MD 21287, USA
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Abstract
The QT Variability Index (QTVI) is a non-invasive measure of repolarization lability that has been applied to a wide variety of subjects with cardiovascular disease. It is a ratio of normalized QT variability to normalized heart rate variability, and therefore includes an assessment of autonomic nervous system tone. The approach assesses beat-to-beat variability in the duration of the QT and U wave in conventional surface electrocardiographic recordings, as well as determines the heart rate variability (HRV) from the same recording. As opposed to T wave alternans, QTVI assesses variance in repolarization at all frequencies. Nineteen studies have published data on QTVI in healthy individuals, while 20 have evaluated its performance in cohorts with cardiovascular disease. Six studies have assessed the utility of QTVI in predicting VT/VF, cardiac arrest, or cardiovascular death. A prospective study utilizing QTVI to determine therapy allocation has not been performed, and therefore the final determination of the value of the metric awaits definitive exploration.
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Affiliation(s)
- Craig P Dobson
- Department of Medicine, Division of Cardiology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA; Walter Reed National Military Medical Center, Bethesda, MD, USA
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QTc interval and its variability in patients with schizophrenia and healthy subjects: implications for a thorough QT study. Int J Neuropsychopharmacol 2012; 15:1535-40. [PMID: 22313550 DOI: 10.1017/s1461145712000077] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We compared heart rate-corrected QT interval (QTc) and its within- and between-subject variability, in ECGs recorded several days apart for 207 patients with schizophrenia (age range 19-60 yr) with age- and gender-matched healthy controls. Patients had higher heart rates (mean±s.d.) than controls [75±15 beats per minute (bpm) vs. 63±10 bpm; p<0.0001]. QTc by Bazett's formula (QTcB) overestimated QTc interval at high heart rates; consequently QTcB was longer in patients (412±24 ms) than in controls (404±24 ms; p=0.0003). QTc by Fridericia's method (QTcF), which was not influenced by heart rate, was comparable (398±22 ms in patients vs. 401±19 ms in controls; p=0.17). Between-subject variability in QTcF was similar in patients (17 ms) and controls (16.2 ms) but within-subject variability was larger (13.1 ms vs. 10 ms, respectively). Thus, a larger sample size is required when thorough QTc studies with a cross-over design are performed in patients with schizophrenia than in healthy subjects; sample size is not increased for studies with a parallel design. Last, QTcF is preferred over QTcB in schizophrenia patients with higher heart rates.
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Effect of Exercise-Based Cardiac Rehabilitation Following Coronary Artery Bypass Surgery on Ventricular Repolarization Indices. J Cardiopulm Rehabil Prev 2011; 31:239-44. [DOI: 10.1097/hcr.0b013e318211e3c0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Johansson M, Karlsson AK, Myredal A, Lidell E. Arterial baroreflex dysfunction after coronary artery bypass grafting. Interact Cardiovasc Thorac Surg 2009; 8:426-30. [DOI: 10.1510/icvts.2008.198747] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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