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Demir FA, Bingöl G, Ersoy İ, Arslan A, Ersoy P, Demir M, Ünlü S. The Relationship between Frontal QRS-T Angle and Vitamin D Deficiency. MEDICINA (KAUNAS, LITHUANIA) 2024; 60:776. [PMID: 38792959 PMCID: PMC11123170 DOI: 10.3390/medicina60050776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/26/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024]
Abstract
Background and Objectives: A deficiency in serum 25-hydroxyvitamin D levels is associated with a number of cardiovascular situations, such as high blood pressure, heart failure, atherosclerotic heart disease, and peripheral artery disease. The frontal QRS-T angle has recently been proposed as a marker of ventricular repolarization. A wider frontal QRS-T angle has been positively correlated with adverse cardiac events. The objective of our study was to examine the association between serum 25-hydroxyvitamin D level and the frontal QRS-T angle. Materials and Methods: A total of 173 consecutive patients aged 18-60 years undergoing routine cardiology check-up evaluation, and not receiving concurrent vitamin D treatment were included in the study. Patients were classified in three groups, depending on their vitamin D levels, and categorized as follows: Group 1-deficient (<20 ng/mL), Group 2-insufficient (20-29 ng/mL), or Group 3-optimal (≥30 ng/mL). The frontal QRS-T angle was determined using the automated reports generated by the electrocardiography machine. Results: The average age of participants was 45.8 (±12.2) years, and 55.5% of participants were female (p < 0.001). Individuals with low vitamin D concentrations exhibited a wider frontal QRS-T angle. It was determined that vitamin D level is an independent predictive factor for the frontal QRS-T angle. Conclusions: As the levels of 25-hydroxyvitamin D decrease, repolarization time assessed by frontal QRS-T angle is widened. Our findings indicate that lower concentrations of vitamin D may increase the susceptibility to ventricular arrhythmia.
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Affiliation(s)
- Fulya Avcı Demir
- Department of Cardiology, Medical Park Hospital, 07160 Antalya, Turkey;
- Department of Cardiology, Istinye University, 34010 Istanbul, Turkey
| | - Gülsüm Bingöl
- Department of Cardiology, Istanbul Arel University, 34537 Istanbul, Turkey;
- Department of Cardiology, Bahcelievler Memorial Hospital, 34180 Istanbul, Turkey
| | - İbrahim Ersoy
- Department of Cardiology, Kepez State Hospital, 07320 Antalya, Turkey;
| | - Akif Arslan
- Department of Cardiology, Medical Park Hospital, 07160 Antalya, Turkey;
- Department of Cardiology, Istinye University, 34010 Istanbul, Turkey
| | - Pınar Ersoy
- Department of Family Medicine, Akdeniz University, 07070 Antalya, Turkey;
| | - Meltem Demir
- Department of Biochemistry, Medikal Park Hospital, 07160 Antalya, Turkey;
- Vocational School of Health Services, Antalya Bilim University, 07110 Antalya, Turkey
| | - Serkan Ünlü
- Department of Cardiology, Gazi University Medical Faculty, 06570 Ankara, Turkey;
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Bingol Tanriverdi T, Tercan M, Patmano G, Tanriverdi Z, Güsun Halitoglu A, Kaya A. The Effect of Low-Flow and Normal-Flow Desflurane Anesthesia on the Frontal QRS-T Angle in Patients Undergoing Rhinoplasty Operation: A Randomized Prospective Study. Cureus 2022; 14:e28920. [PMID: 36225439 PMCID: PMC9541937 DOI: 10.7759/cureus.28920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2022] [Indexed: 11/26/2022] Open
Abstract
Introduction: Low-flow anesthesia (LFA) has gained more interest worldwide owing to its economic and ecological advantages compared to normal-flow anesthesia (NFA). Desflurane is one of the commonly used anesthetic agents for LFA, but it may prolong myocardial repolarization. Frontal QRS-T angle (f[QRS-T]a) is a novel marker of myocardial repolarization. To our knowledge, no study has compared the effect of LFA and NFA on f(QRS-T)a. In this study, we aimed to compare the effect of the LFA and NFA with desflurane on f(QRS-T)a in patients undergoing rhinoplasty operation. Methods: A total of 80 patients undergoing rhinoplasty operations were included in this prospective study. The patients were randomized into two groups as follows: LFA (n = 40) and NFA (n = 40). The frontal QRS-T angle was calculated from the automatic report of the electrocardiography device (Nihon Kohden, Tokyo, Japan). It was recorded at the following time points: T1: preoperative (basal), T2: immediately after anesthesia induction, T3: immediately after endotracheal intubation, T4: 5 min after endotracheal intubation, T5: 15 min after endotracheal intubation, T6: 30 min after endotracheal intubation, T7: 60 min after endotracheal intubation, T8: end of the operation, T9: 15 min after the end of the operation. Results: Baseline clinical characteristics and laboratory parameters were similar between the two groups. In the LFA group, f(QRS-T)a was significantly increased at only the T3 time point when compared to T1 (P = 0.003). However, in the NFA group, f(QRS-T)a was significantly increased at T3, T4, T5, T6, T7, T8, and T9 time points when compared to the T1 value (P < 0.05, for all). On the other hand, fQRS-Ta was significantly higher in the NFA group than in the LFA group at T4, T5, and T6 time points. Conclusion: In our study, we have shown for the first time that NFA significantly increased the f(QRS-T)a, whereas LFA did not significantly increase the f(QRS-T)a except for immediately after the endotracheal intubation. It was also detected that f(QRS-T)a was significantly higher in the NFA group compared to that in the LFA group. Therefore, it can be concluded that LFA has more protective effects on myocardial repolarization than NFA.
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Tascanov MB, Tanriverdi Z, Gungoren F, Tapar GG, Bicer A. The relationship between myocardial bridge and frontal
QRS‐T
angle. J Arrhythm 2022; 38:772-777. [PMID: 36237851 PMCID: PMC9535755 DOI: 10.1002/joa3.12774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 08/09/2022] [Accepted: 08/22/2022] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Zulkif Tanriverdi
- Faculty of Medicine, Sanliurfa Department of Cardiology Harran University Turkey
| | - Fatih Gungoren
- Faculty of Medicine, Sanliurfa Department of Cardiology Harran University Turkey
| | | | - Asuman Bicer
- Faculty of Medicine, Sanliurfa Department of Cardiology Harran University Turkey
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KUŞ G, ÇAĞIRCI G. FRONTAL QRS-T AÇISI İLE AMBULATUAR 24 SAAT HOLTERDE PREMATÜR VENTRİKÜLER KONTRAKSİYON YÜKÜ ARASINDAKİ İLİŞKİ. ACTA MEDICA ALANYA 2022. [DOI: 10.30565/medalanya.1131541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
AMAÇ
Sık prematür ventriküler kontraksiyonlar (PVK), ventriküler fonksiyonun bozulmasına veya ventriküler kavitelerin genişlemesine neden olabilir. Frontal düzlem QRS-T [f(QRS-T)] açısı, miyokardın elektrofizyolojik özelliklerindeki kararsızlığın bir göstergesidir ve aritmilerle ilişkilidir. Bu çalışma, ventriküler repolarizasyon heterojenitesinin bir belirteci olarak f(QRS-T) açısının, ambulatuar 24 saatlik holterde prematüre ventriküler kontraksiyon yükünü tahmin edip etmediğini araştırmayı amaçlamıştır.
METHOD
Çalışmada 100 hasta mevcuttu. Hastalar 24 saatlik Holter izleminde PVK yüklerine göre “sık PVK” ve “nadir PVK” olarak iki gruba ayrıldı. Laboratuar ve frontal plan QRS-T açısı dahil olmak üzere bazı ambulatuar elektrokardiyografi parametreleri iki grup arasında karşılaştırıldı.
BULGULAR
Frontal QRS-T açısı (63.34±37.86°'ye karşı 23.46±14.29° p
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Hocanli I, Tanriverdi Z, Kabak M, Gungoren F, Tascanov MB. The relationship between frontal QRS-T angle and the severity of newly diagnosed chronic obstructive pulmonary disease. Int J Clin Pract 2021; 75:e14500. [PMID: 34117683 DOI: 10.1111/ijcp.14500] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 05/17/2021] [Accepted: 06/10/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Chronic obstructive pulmonary disease (COPD) is characterised by persistent airflow restriction and respiratory symptoms. Studies demonstrated that cardiac arrhythmias and cardiovascular mortality increased in these patients as a result of altered myocardial repolarization. Frontal QRS-T angle is a novel marker of myocardial depolarization and repolarization heterogeneity. In this study, we aimed to investigate the relationship between frontal QRS-T angle and disease severity in patients with newly diagnosed COPD. METHODS A total of 104 newly diagnosed COPD patients were included in this study. Patients were divided into two groups according to GOLD (Global Obstructive Lung Disease) stage as follows: patients with mild and moderate COPD (group I), and severe and very severe COPD (group II). Frontal QRS-T angle was calculated from the automatic report of the electrocardiography device. RESULTS Frontal QRS-T angle was significantly higher in group II patients compared with in group I patients (43.0 [25.5-60.0] vs. 20.0 [12.0-32.0], P < .001). The best cut-off value of frontal QRS-T angle for predicting severe-very severe COPD was ≥34.5°. Correlation analysis showed that frontal QRS-T angle was negatively correlated with FEV1/FVC (r = -.524, P < .001) and MEF25-75 (r = -.453, P < .001). Multivariate logistic regression analysis was showed that frontal QRS-T angle was the only independent predictor of severe-very severe COPD (OR: 1.051, 95% CI: 1.024-1.079, P < .001). CONCLUSIONS Frontal QRS-T angle is an easily obtainable marker form surface electrocardiography. In this study, we have shown for the first time that frontal QRS-T angle was significantly increased in patients with severe and very severe COPD.
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Affiliation(s)
- Iclal Hocanli
- Department of Chest Diseases, Faculty of Medicine, Harran University, Sanliurfa, Turkey
| | - Zulkif Tanriverdi
- Department of Cardiology, Faculty of Medicine, Harran University, Sanliurfa, Turkey
| | - Mehmet Kabak
- Clinic of Chest Diseases, Mardin State Hospital, Mardin, Turkey
| | - Fatih Gungoren
- Department of Cardiology, Faculty of Medicine, Harran University, Sanliurfa, Turkey
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Tascanov MB, Tanriverdi Z, Gungoren F, Besli F, Bicer Yesilay A, Altiparmak HI, Bayram G, Demir K. The effect of propofol on frontal QRS‐T angle in patients undergoing elective colonoscopy procedure. J Clin Pharm Ther 2019; 45:185-190. [DOI: 10.1111/jcpt.13055] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/09/2019] [Accepted: 08/23/2019] [Indexed: 01/18/2023]
Affiliation(s)
| | - Zulkif Tanriverdi
- Department of Cardiology Faculty of Medicine Harran University Sanliurfa Turkey
| | - Fatih Gungoren
- Department of Cardiology Faculty of Medicine Harran University Sanliurfa Turkey
| | - Feyzullah Besli
- Department of Cardiology Faculty of Medicine Harran University Sanliurfa Turkey
| | | | | | - Gursel Bayram
- Department of Gastroentrology Tokat Medical Park Hospital Tokat Turkey
| | - Kadir Demir
- Department of Anesthesia Tokat State Hospital Tokat Turkey
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Braschi A, Abrignani MG, Francavilla VC, Abrignani V, Francavilla G. Age- and sex-based reference ranges for non-invasive ventricular repolarisation parameters. Int J Clin Pract 2017; 71. [PMID: 28508456 DOI: 10.1111/ijcp.12949] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 03/12/2017] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Some electrocardiographic parameters are able to assess indirectly ventricular repolarisation homogeneity. It is consequently essential to discriminate between normal and abnormal values in clinical decision-making. Considering there is still not a consensus about normal cut-off values, the aim of this study was to document reference intervals in all age groups of a healthy population, providing for age- and sex-percentile tables, which can be used easily and quickly in clinical practice. METHODS We evaluated repolarisation markers in 606 sex-matched participants aged 1 day-94 years. Each subject underwent a 12-lead electrocardiogram at rest, and the following parameters were measured: QT, corrected QT, QTpeak, Tpeak-Tend, Tpeak-Tend dispersion, Tpeak-Tend/QT and QTpeak/QT ratio. RESULTS A relationship was demonstrated between age and QTpeak, Tpeak-Tend, QT and QTc. In children, QTpeak, Tpeak-Tend and QT intervals increased linearly with age. In adolescents, all the three parameters remained stable. In adults, QTpeak and QT showed a further significant increase. On the contrary, Tpeak-Tend interval was longer in adults aged between 20 and 64 years than in participants aged 65 years or over, but the difference was not statistically significant. Male vs female participants showed longer Tpeak-Tend intervals; this sex difference was not statistically significant at birth and during childhood, whereas it was in adolescents and in adults. CONCLUSIONS Repolarisation parameters showed age- and sex-based variations, which are important to know to differentiate normal from pathological values.
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Affiliation(s)
- Annabella Braschi
- Department of Internal and Specialistic Medicine, Palermo University Hospital, Palermo, Italy
| | | | - Vincenzo C Francavilla
- Department of Internal and Specialistic Medicine, Palermo University Hospital, Palermo, Italy
| | | | - Giuseppe Francavilla
- Department of Internal and Specialistic Medicine, Palermo University Hospital, Palermo, Italy
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Abstract
The electrocardiographic QT interval has been extensively studied in ischaemic heart disease. Recently, there has been increasing interest in the relationship between diabetes and QT abnormalities. QT prolongation and increased QTd have been shown to predict cardiac death in both type 1 and type 2 diabetes mellitus. Although there is general agreement that QT interval is affected by cardiac ischaemia, the effect of hyperglycaemia on QT measures is controversial. There are also problems surrounding QTd. First, there is controversy as to whether the measure has any physiological meaning; secondly, there is no universally accepted method of measurement and hence no consensus about the upper limit of normal. Nevertheless, several studies have shown increased QTd in diabetic patients suggesting that assessment of the QT interval could be a cost effective way of stratifying aggressive treatment could be directed appropriately to such patients according to cardiovascular risk so that improve outcome.
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Affiliation(s)
| | - Miles Fisher
- Department of Diabetes, Glasgow Royal Infirmary, Glasgow, G4 0SF, UK
| | - Peter W Macfarlane
- University of Glasgow, Division of Cardiovascular and Medical Sciences, Royal Infirmary, Glasgow, G31 2ER, UK
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Comparison of QT-interval and variability index methodologies in individuals with spinal cord injury. Spinal Cord 2016; 55:274-278. [PMID: 27481091 DOI: 10.1038/sc.2016.118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/20/2016] [Accepted: 06/22/2016] [Indexed: 01/10/2023]
Abstract
STUDY DESIGN Within-group comparison. OBJECTIVES Individuals with spinal cord injury (SCI) demonstrate an elevated risk for cardiac arrhythmias as indicated by an elevated QT-variability index (QTVI). The methodology measuring the QTVI, however, is not standardized, and therefore the purpose of this investigation is to determine whether the threshold and tangent methods of QT-interval measurement, as well as the electrocardiographic (ECG) epoch duration, influence the QTVI in individuals with SCI. SETTING Ontario, Canada. METHODS Ten minutes of resting ECG data were collected and analyzed from 14 individuals with SCI (C2-L3; ASIA Impairment Scale (AIS) A-D; 11.5±9.4 years post injury). The QTVI was analyzed via the threshold and tangent methods of QT-interval measurement, as well as from 1-, 5- and 10-min ECG epochs. RESULTS The threshold method produced significantly higher QTVI values compared with the tangent method. The QTVI from a 1-min epoch was significantly higher compared with that from 5- and 10-min epochs. The QTVI values acquired from the threshold method were shown to have higher reproducibility compared with those from the tangent method. There were no differences in QTVI values between participants with lesions above and below T1, as shown by both methods of QT-interval measurement. CONCLUSION The method of QT-interval measurement and the length of ECG epoch influence QTVI values in individuals with SCI. The methodology of QTVI analysis must be standardized in studies involving SCI individuals to reduce the variability accounted by methodological inconsistency.
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Cakici M, Dogan A, Cetin M, Suner A, Caner A, Polat M, Kaya H, Abus S, Akturk E. Negative effects of acute sleep deprivation on left ventricular functions and cardiac repolarization in healthy young adults. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2014; 38:713-22. [PMID: 25353305 DOI: 10.1111/pace.12534] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/21/2014] [Accepted: 09/16/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND Sleep deprivation (SD) is associated with an increased incidence of adverse cardiovascular events, we aimed to determine the impact of acute SD on structural and functional alterations of the left ventricle (LV) and on electrocardiogram (ECG) markers including T wave peak-to-end interval (TpTe), QT interval, and TpTe/QT ratio in healthy subjects after a night of SD. METHODS The study population consisted of 40 healthy young adults (19 males, 21 females; mean age: 28.2 ± 3.86 years). Echocardiographic images and ECGs were obtained from the participants after a night of regular sleep (RS) and SD. The average sleep time of the subjects was 6.67 ± 1.76 hours during RS and 1.25 ± 0.74 hours during a night of SD. RESULTS The myocardial performance index, isovolumic relaxation time, and deceleration time values were significantly higher after SD. In addition, the corrected TpTe interval, corrected QT interval (QTc) max, and TpTe/QT ratio were significantly increased after a night of SD when compared with a night of RS (78.5 ± 6.8 ms vs 70.7 ± 7.6 ms, P < 0.001; 407.5 ± 18.6 ms vs 395.07 ± 21.3 ms, P = 0.001; and 0.189 ± 0.014 ms vs 0. 0.179 ± 0.016 ms, P < 0.001, respectively). However, subjects had similar QTp interval values (defined as beginning of the QRS complex to peak of the T wave) after a night of SD as a night of RS (294.6 ± 19.0 vs 291.9 ± 18.5, P = 233). CONCLUSION Our crossover study revealed the presence of subclinical LV diastolic functional changes and increased QT intervals, TpTe intervals, and TpTe/QT ratios in healthy young adults after one night SD. Therefore, the increased QT interval occurred secondary to the increased TpTe interval in this population.
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Affiliation(s)
- Musa Cakici
- Department of Cardiology, School of Medicine, Adiyaman University, Adiyaman, Turkey
| | - Adnan Dogan
- Department of Cardiology, School of Medicine, Dumlupinar University, Kutahya, Turkey
| | - Mustafa Cetin
- Department of Cardiology, School of Medicine, Adiyaman University, Adiyaman, Turkey
| | - Arif Suner
- Department of Cardiology, School of Medicine, Adiyaman University, Adiyaman, Turkey
| | - Asli Caner
- Department of Biological and Medical Science, Oxford Brookes University, Oxford, UK
| | - Mustafa Polat
- Department of Cardiology, School of Medicine, Adiyaman University, Adiyaman, Turkey
| | - Hakan Kaya
- Department of Cardiology, School of Medicine, Adiyaman University, Adiyaman, Turkey
| | - Sabri Abus
- Department of Cardiology, School of Medicine, Adiyaman University, Adiyaman, Turkey
| | - Erdal Akturk
- Department of Cardiology, School of Medicine, Adiyaman University, Adiyaman, Turkey
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Xue J, Rowlandson I. The detection of T-wave variation linked to arrhythmic risk: an industry perspective. J Electrocardiol 2013; 46:597-607. [PMID: 24210024 DOI: 10.1016/j.jelectrocard.2013.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Indexed: 01/10/2023]
Abstract
Although the scientific literature contains ample descriptions of peculiar patterns of repolarization linked to arrhythmic risk, the objective quantification and classification of these patterns continues to be a challenge that impacts their widespread adoption in clinical practice. To advance the science, computerized algorithms spawned in the academic environment have been essential in order to find, extract and measure these patterns. However, outside the strict control of a core lab, these algorithms are exposed to poor quality signals and need to be effective in the presence of different forms of noise that can either obscure or mimic the T-wave variation (TWV) of interest. To provide a practical solution that can be verified and validated for the market, important tradeoffs need to be made that are based on an intimate understanding of the end-user as well as the key characteristics of either the signal or the noise that can be used by the signal processing engineer to best differentiate them. To illustrate this, two contemporary medical devices used for quantifying T-wave variation are presented, including the modified moving average (MMA) for the detection of T-wave Alternans (TWA) and the quantification of T-wave shape as inputs to the Morphology Combination Score (MCS) for the trending of drug-induced repolarization abnormalities.
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Pattern recognition analysis of digital ECGs: Decreased QT measurement error and improved precision compared to semi-automated methods. J Electrocardiol 2013; 46:118-25. [DOI: 10.1016/j.jelectrocard.2012.11.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Indexed: 11/21/2022]
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Aksoy SM, Cay S, Cagirci G, Sen N. Nebivolol therapy improves QTc and QTcd parameters in heart failure patients. Cardiovasc J Afr 2013; 23:191-3. [PMID: 22614660 PMCID: PMC3721958 DOI: 10.5830/cvja-2011-046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 08/30/2011] [Indexed: 11/28/2022] Open
Abstract
Aim It has previously been shown that β-blocker therapy reduces QT dynamics in heart failure patients. The aim of this study was to demonstrate this improvement with the third-generation β-blocker, nebivolol. Methods A total of 72 heart failure patients with systolic dysfunction were included in the study. Corrected QT (QTc) and QT dispersion (QTcd) were measured manually by two independent observers at baseline and after nebivolol use (5 mg/day) in the first and third months of follow up. Results Both QTc and QTcd were found to be significantly reduced in the first (455.3 ± 26.7 vs 441.2 ± 25.7 ms, p < 0.001 for QTc, and 65.6 ± 5.3 vs 58.2 ± 5.6 ms, p = 0.001 for QTcd) and third months (455.3 ± 26.7 vs 436.0 ± 28.7 ms, p < 0.001 for QTc, and 65.6 ± 5.3 vs 56.0 ± 6.2 ms, p < 0.001 for QTcd) compared with baseline values. Conclusion Nebivolol was associated with improved QT dynamics in heart failure patients with systolic dysfunction.
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Affiliation(s)
- S M Aksoy
- Department of Anesthesiology, Diskapi Yildirim Beyazit Education and Research Hospital, Ankara, Turkey
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A multidifferentiator-based approach to the reliable determination of T-wave offset in electrocardiograms. J Electrocardiol 2011; 44:330-9. [DOI: 10.1016/j.jelectrocard.2010.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Indexed: 11/20/2022]
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Alexandraki KI, Kaltsas GA, Vouliotis AI, Papaioannou TG, Trisk L, Zilos A, Korbonits M, Besser GM, Anastasakis A, Grossman AB. Specific electrocardiographic features associated with Cushing's disease. Clin Endocrinol (Oxf) 2011; 74:558-64. [PMID: 21470280 DOI: 10.1111/j.1365-2265.2011.03975.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Hypercortisolaemia is associated with an increased risk of cardiovascular disease (CVD), either through a direct action on the myocardium or by increased traditional cardiovascular risk factors. The aim of this study was to investigate whether the alterations in the ECG in Cushing's disease (CD) are predictable from risk factor analysis alone. DESIGN In 79 patients with a diagnosis of CD, retrospectively recruited, ECG features [corrected for heart rate QT (QTc), QTc dispersion (QTcd), left ventricular hypertrophy (ECG-LVH), right ventricular hypertrophy (ECG-RVH)], systolic (SBP) and diastolic (DBP) blood pressure were assessed. Biochemical, hormonal (cortisol at 09·00 h or cortisol day curve, CDC) and carbohydrate abnormalities (CHA), history of hypertension and cardiovascular disease were recorded. For comparison reasons, a group of 42 healthy subjects matched for gender, age and body mass index previously subjected to ECG assessment were selected. RESULTS In patients with CD, we noted the following prevalence: metabolic syndrome 39%, hypertension 81%, CVD 21·5%, hypercholesterolaemia 37%, hypertriglyceridaemia 29%, CHA 41%, but a history of cardiac dysrhythmia was only noted in a single patient. No difference in QTc or QTcd was shown between patients with normal or low potassium levels. QTcd >50 ms was associated with both increased ECG-LVH and ECG-RVH. When compared to the control group, patients had longer QTcd (P < 0·001), more prevalent LVH (P < 0·001) and RVH (P = 0·001), and higher SBP and DBP (P < 0·001), but similar QTc. Both CD and ECG evidence of LVH predicted prolonged QTcd, but the association of CD with a prolonged QTcd was independent of other risk factors, including hypertension. CONCLUSIONS Prolonged QTcd in association with ECG evidence of LVH appears to be the specific feature of CD. This may be relevant in the choice of medical therapy for CD and for consideration of treatment of the comorbidities that are associated with hypercortisolaemia.
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Alper AT, Akyol A, Hasdemir H, Nurkalem Z, Güler Ö, Güvenç TS, Erdinler İ, Çakmak N, Eksik A, Gürkan K. Glue (Toluene) Abuse: Increased QT Dispersion and Relation with Unexplained Syncope. Inhal Toxicol 2008; 20:37-41. [DOI: 10.1080/08958370701758304] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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OZER ORHAN, OZBALA BURCU, SARI IBRAHIM, DAVUTOGLU VEDAT, MADEN EMIN, BALTACI YASEMIN, YAVUZ SEMA, AKSOY MEHMET. Acute Sleep Deprivation is Associated with Increased QT Dispersion in Healthy Young Adults. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2008; 31:979-84. [DOI: 10.1111/j.1540-8159.2008.01125.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Kardesoglu E, Aparci M, Uzun G, Suleymanoglu S, Uz O, Onem Y, Ay H, Kucukardali Y, Ozkan S. Hyperbaric Oxygen Therapy Decreases QT Dispersion in Diabetic Patients. TOHOKU J EXP MED 2008; 215:113-7. [DOI: 10.1620/tjem.215.113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Ejder Kardesoglu
- Department of Cardiology, Gulhane Military Medical Academy, Haydarpasa Teaching Hospital
| | - Mustafa Aparci
- Department of Cardiology, Gulhane Military Medical Academy, Haydarpasa Teaching Hospital
| | - Gunalp Uzun
- Department of Underwater and Hyperbaric Medicine, Gulhane Military Medical Academy, Haydarpasa Teaching Hospital
| | - Selami Suleymanoglu
- Department of Pediatric Cardiology, Gulhane Military Medical Academy, Haydarpasa Teaching Hospital
| | - Omer Uz
- Department of Cardiology, Gulhane Military Medical Academy, Haydarpasa Teaching Hospital
| | - Yalcin Onem
- Department of Internal Medicine, Gulhane Military Medical Academy, Haydarpasa Teaching Hospital
| | - Hakan Ay
- Department of Underwater and Hyperbaric Medicine, Gulhane Military Medical Academy, Haydarpasa Teaching Hospital
| | - Yasar Kucukardali
- Department of Internal Medicine, Gulhane Military Medical Academy, Haydarpasa Teaching Hospital
| | - Sezai Ozkan
- Department of Anesthesiology and Reanimation, Gulhane Military Medical Academy, Haydarpasa Teaching Hospital
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20
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Dursunoglu D, Dursunoglu N. Effect of CPAP on QT interval dispersion in obstructive sleep apnea patients without hypertension. Sleep Med 2007; 8:478-83. [PMID: 17512787 DOI: 10.1016/j.sleep.2006.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2006] [Revised: 08/07/2006] [Accepted: 08/08/2006] [Indexed: 12/18/2022]
Abstract
OBJECTIVES Delayed cardiac repolarization leading to prolongation of the QT interval is a well-characterised precursor of arrhythmias. Obstructive sleep apnea (OSA) might cause arrhythmias, since QT corrected interval dispersion (QTcd) is increased in these patients. We aimed to determine the effect of nasal continuous positive airway pressure (CPAP) therapy on QTcd in OSA patients without hypertension. METHODS An overnight polysomnography (PSG) and a standard 12-lead electrocardiogram (ECG) were performed on 49 subjects without hypertension, diabetes mellitus, cardiac or pulmonary disease or any hormonal, hepatic, renal or electrolyte disorders. In 29 moderate-severe OSA (apnea-hypopnea index: AHI15) patients, QTd (defined as the difference between the maximum and minimum QT interval) and QTcd were calculated using the Bazzet formula at baseline and after six months of CPAP therapy. RESULTS Eighteen patients were compliant with nasal CPAP, and mean age was 46.5+/-4.9 years. Patients had high body mass index (BMI: 30.6+/-4.0 kg/m(2)), but there was no change in either BMI or blood pressure after six months. A strong positive correlation was shown between QTcd and AHI (p<0.001, r=0.913). The QTcd at baseline (54.5+/-8.7 ms) significantly decreased after CPAP therapy (35.5+/-4.2 ms, p<0.001), although it did not significantly change in 11 non-compliant patients. CONCLUSION In OSA patients without hypertension, CPAP therapy improves the inhomogeneity of repolarization via a significant decrease in QTcd.
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Affiliation(s)
- Dursun Dursunoglu
- Pamukkale University Medical Faculty, Department of Cardiology, 20200 Kinikli, Denizli, Turkey.
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21
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Di Iorio BR, Bortone S, Piscopo C, Grimaldi P, Cucciniello E, D'Avanzo E, Mondillo F, Cillo N, Bellizzi V. Cardiac Vascular Calcification and QT Interval in ESRD Patients: Is There a Link? Blood Purif 2006; 24:451-9. [PMID: 16940716 DOI: 10.1159/000095362] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2006] [Accepted: 06/28/2006] [Indexed: 11/19/2022]
Abstract
We will present our experience and our preliminary data about the correlation between cardiac calcification and QT interval (and QT dispersion) in uraemia. We studied 32 haemodialysis (HD) patients (age 69 +/- 16 years, time on dialysis 32 +/- 27 months) and 12 chronic kidney disease stage 4 (CKD-4) patients (age 66 +/- 17 years, uraemia duration 38 +/- 16 months). The patients were characterized by a good mineral control, as shown by serum phosphate levels (3.6 +/- 1.3 mg/dl in CKD-4 and 4.3 +/- 1.6 mg/dl in HD patients) and Ca x P product (46 +/- 17 and 49 +/- 16 mg(2)/dl(2), respectively). The parathyroid hormone levels were higher in HD than CKD-4 patients (p < 0.0001). A TC score >400 was found to be highly prevalent in both groups. Significantly more HD patients (62.5%) showed cardiac calcification than CKD-4 patients (33%; p = 0.01). The patients were matched for TC scores higher or lower than 400. The two groups differed by gender (p < 0.05), age (p = 0.026), frequency of diabetes mellitus (p < 0.01), uraemia follow-up period (p < 0.001), low-density lipoprotein cholesterol level (p = 0.009), Ca x P product (p = 0.002), parathyroid hormone level (p < 0.0001), and corrected QT dispersion (p < 0.0001). The QT interval was higher in HD and CKD-4 patients with higher TC scores (approximately 11%), but QT interval dispersion was significantly higher in patients with TC scores >400. QT dispersion showed a linear correlation with TC scores in both groups (r = 0.899 and p < 0.0001 and r = 0.901 and p < 0.0001). Male gender, age, time (months) of uraemia, low-density lipoprotein cholesterol, albumin, calcium x phosphorus product, parathyroid hormone, and TC score are important determinants of QT dispersion. Our data show that it is possible to link dysrhythmias and cardiac calcification in uraemic patients.
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22
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Batchvarov V, Kaski JC, Parchure N, Dilaveris P, Brown S, Ghuran A, Färbom P, Hnatkova K, Camm AJ, Malik M. Comparison between ventricular gradient and a new descriptor of the wavefront direction of ventricular activation and recovery. Clin Cardiol 2006; 25:230-6. [PMID: 12018881 PMCID: PMC6654433 DOI: 10.1002/clc.4950250507] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Total R T cosine (TCRT) is a new descriptor of repolarization heterogeneity that quantifies the deviation between the directions of ventricular depolarization and repolarization. It revives the old concept of ventricular gradient (VG). HYPOTHESIS Our goal was to examine whether TCRT and VG contain nonredundant information by comparing their reaction to autonomic tests, namely, postural changes and Valsalva maneuver. METHODS Digital 12-lead electrocardiograms were recorded in 16 patients with cardiovascular syndrome X (SX, chest pain, exercise-induced ST-depression, normal coronary arteries, 3 men, age 60 +/- 9 years) and 40 healthy volunteers (31 men, age 33 +/- 7 years) during postural changes and Valsalva maneuver. The angle (VGA) [degrees] and magnitude (VGM) [ms.mV] of VG in reconstructed XYZ leads and TCRT (average cosine of the angles between the QRS and T vectors in mathematically reconstructed three-dimensional space) were calculated. RESULTS (mean +/- standard of the mean): In healthy subjects, VGM and TCRT decreased, whereas VGA increased in the sitting and standing compared with supine position (TCRT: 0.61 +/- 0.05,0.47 +/- 0.06,0.29 +/- 0.08, supine, sitting, and standing, p < 0.05) and during phase II Valsalva (TCRT: 0.47 +/- 0.06 vs. 0.61 +/- 0.05, p < 0.01 in supine, 0.24 +/- 0.08 vs. 0.37 +/- 0.07, p < 0.01 in standing). In patients with SX, VGM decreased in the standing position, VGA did not change significantly, while TCRT decreased only in patients without T-wave abnormalities (n = 9) (TCRT in standing and supine: 0.55 +/- 0.09 vs. 0.68 +/- 0.08, p < 0.05). VG(M) increased during Valsalva in patients with SX. Total R T cosine correlated strongly with VGA (r = -0.84, p < 0.00001) and, unlike VGM, did not correlate with heart rate. CONCLUSIONS Ventricular gradient and TCRT contain nonredundant information. In healthy subjects, they react sensitively to autonomic provocation. In patients with SX, their reaction is attenuated, which suggests disturbance of the autonomic control of repolarization.
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Affiliation(s)
- Velislav Batchvarov
- Department of Cardiological Sciences, St George's Hospital Medical School, London, UK.
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23
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Brendorp B, Elming H, Jun L, Køber L, Torp-Pedersen C. The prognostic value of QTc interval and QT dispersion following myocardial infarction in patients treated with or without dofetilide. Clin Cardiol 2006; 26:219-25. [PMID: 12769249 PMCID: PMC6654634 DOI: 10.1002/clc.4960260505] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Acute myocardial infarction (MI) is associated with an increased risk of death, with a 1-year mortality close to 10% in patients discharged from hospital alive. During the first year following MI, close to 50% of deaths are assumed to be due to arrhythmic events. HYPOTHESIS The study was undertaken to determine the interaction between dofetilide treatment and pretreatment QTc interval and QT dispersion regarding mortality in patients with left ventricular (LV) dysfunction and a recent MI. METHODS The study population consisted of 894 patients with a recent MI and LV systolic dysfunction, who were randomized to receive dofetilide or placebo. The study was a substudy of the Danish Investigations of Arrhythmia and Mortality on Dofetilide-MI (DIAMOND-MI). RESULTS During a minimum of 1-year follow-up, 261 (29%) patients died. Baseline QTc interval did not hold any prognostic value on mortality for placebo-treated patients. When pretreatment QTc interval was <429 ms, dofetilide resulted in a 45% reduction of mortality (hazard ratio 0.55, 95% confidence limits 0.34-0.88, p<0.02) compared with placebo. When QTc interval was >429 ms, dofetilide did not influence mortality significantly. This study revealed no statistically significant relation between QT dispersion, dofetilide treatment, and mortality. CONCLUSION In patients with a recent MI, LV dysfunction, and a short baseline QTc interval, dofetilide is associated with significant survival benefit. This benefit is not seen with a longer QTc interval. QT dispersion is not a risk factor in this population.
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Affiliation(s)
- Bente Brendorp
- Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark.
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Dota C, Skallefell B, Edvardsson N, Fager G. Computer-based analysis of dynamic QT changes: toward high precision and individual rate correction. Ann Noninvasive Electrocardiol 2006; 7:289-301. [PMID: 12431306 PMCID: PMC7027718 DOI: 10.1111/j.1542-474x.2002.tb00177.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND New strategies are needed to improve the results of automatic measurement of the various parts of the ECG signal and their dynamic changes. METHODS The EClysis software processes digitally-recorded ECGs from up to 12 leads at 500 Hz, using strictly defined algorithms to detect the PQRSTU points and to measure ECG intervals and amplitudes. Calculations are made on the averaged curve of each sampling period (beat group) or as means +/- SD for beat groups, after being analyzed at the individual beat level in each lead. Resulting data sets can be exported for further statistical analyses. Using QT and R-R measured on beat level, an individual correction for the R-R dependence can be performed. RESULTS EClysis assigns PQRSTU points and intervals in a sensitive and highly reproducible manner, with coefficients of variation in ECG intervals corresponding to ca. 2 ms in the simulated ECG. In the normal ECG, the CVs are 2% for QRS, 0.8% for QT, and almost 6% for PQ intervals. EClysis highlights the increase in QT intervals and the decrease of T-wave amplitudes during almokalant infusion versus placebo. Using the observed linear or exponential relationships to adjust QT for R-R dependence in healthy subjects, one can eliminate this dependence almost completely by individualized correction. CONCLUSIONS The EClysis system provides a precise and reproducible method to analyze ECGs.
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Affiliation(s)
- Corina Dota
- Experimental Medicine, AstraZeneca R & D Mölndal, S-431 83 Mölndal, Sweden.
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Arildsen H, Christiansen EH, Pedersen AK, Mølgaard H. Reproducibility of QT parameters derived from 24-hour ambulatory ECG recordings in healthy subjects. Ann Noninvasive Electrocardiol 2006; 6:24-31. [PMID: 11174859 PMCID: PMC7027613 DOI: 10.1111/j.1542-474x.2001.tb00082.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
AIM To estimate the reproducibility of QT parameters derived from 24-hour ambulatory ECG recordings. METHOD Ten healthy volunteers aged 25 to 41 years participated. In two 24-hour ambulatory ECG recordings obtained 1 day apart, the QT interval was measured manually at stable heart rates in approximately 16 periods during daytime and 6 periods during nighttime. The association between the QT and RR interval was described by linear regression for day and nighttime separately and the following QT parameters were calculated: the QT interval at heart rate 60 beats/min during daytime (QT(60)day), slope(day), slope(night), and the difference in QT(60) between day and nighttime (DeltaQT(60)). The QT parameters were assessed four times for each participant to discriminate method inaccuracy from day to day variation. The reproducibility was estimated as the coefficient of repeatability, the relative error, and the ratio between within-subject variability and between-subject variability. RESULTS The coefficient of repeatability, the relative error and the ratio, respectively, were 19 ms, 1.8% and 0.5 for QT(60)day, 0.076, 21% and 0.68 for slope(day), 0.116, 43% and 1.37 for slope(night), and 37 ms, 325% and 1.19 for DeltaQT(60) when estimating the overall day to day reproducibility. Inaccuracy of QT measurement accounted for approximately 40% of this variation, whereas the error caused by selecting segments was small. CONCLUSION QT(60)day has a high reproducibility and may with advantage replace the conventional QT interval measured on a resting ECG. To assess QT dynamics, the slope of the regression line during daytime is suitable and the short term reproducibility acceptable for clinical trials. Regarding slope(night) and DeltaQT(60), the variation is high and the parameters should be used with caution.
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Affiliation(s)
- H Arildsen
- Department of Cardiology (Research unit), Skejby University Hospital, DK-8200 Aarhus N, Denmark.
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Yi G, Poloniecki J, Dickie S, Elliott PM, Malik M, McKenna WJ. Is QT dispersion associated with sudden cardiac death in patients with hypertrophic cardiomyopathy? Ann Noninvasive Electrocardiol 2006; 6:209-15. [PMID: 11466139 PMCID: PMC7027614 DOI: 10.1111/j.1542-474x.2001.tb00110.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
QT dispersion is significantly greater in patients with hypertrophic cardiomyopathy (HCM) than that in healthy subjects. Few data exist regarding the prognostic value of QT dispersion in HCM. In this study, we retrospectively investigated the association between QT dispersion and sudden cardiac death in 46 patients with HCM (mean 33.1 +/- 15.5 years, 32 men). The case group consisted of 23 HCM patients who died suddenly, and the control group consisted of 23 HCM patients who survived uneventfully during follow-up. Study patients were pair-matched for age, gender, and maximum left ventricular wall thickness. QT dispersion (maximum minus minimum QT interval) was manually measured on early 12-lead ECGs using a digitizing board. An in-house program was used for calculating QT interval, QT dispersion, JT interval, and JT dispersion (maximum minus minimum J point to T end interval). Patients in the case group tended to have shorter RR intervals than those in the control group (777 +/- 171 vs 856 +/- 192 ms, P = 0.08). Maximum corrected QT and JT intervals did not discriminate the case group from controls (489 +/- 29 vs 479 +/- 27 ms, P = NS; 375 +/- 36 vs 366 +/- 22 ms, P = NS, respectively). Greater QT dispersion and JT dispersion were found in the case group compared with controls (74 +/- 28 vs 59 +/- 21 ms, P = 0.02 and 76 +/- 32 vs 59 +/- 26 ms, P = 0.03, respectively). The measurements of maximum QT, JT, and T peak to T end intervals, precordial QT and JT dispersion, and T peak and T end dispersion were all comparable between the two groups (P = NS for all). No systematic changes in ECG measurements were found from late ECGs of the case group compared to those from early ECGs (P = NS). No correlation between maximum left ventricular wall thickness and QT dispersion, JT dispersion, maximum QTc or JTc intervals was observed (r < 0.29, P > 0.05 for all). Our results show that increased QT dispersion and JT dispersion is weakly associated with sudden cardiac death in the selected patients with HCM.
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Affiliation(s)
- G Yi
- Department of Cardiological Sciences, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, UK.
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Lund K, Perkiömäki JS, Brohet C, Elming H, Zaïdi M, Torp-Pedersen C, Huikuri HV, Nygaard H, Kirstein Pedersen A. The prognostic accuracy of different QT interval measures. Ann Noninvasive Electrocardiol 2006; 7:10-6. [PMID: 11844286 PMCID: PMC7027618 DOI: 10.1111/j.1542-474x.2001.tb00133.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The QT intervals accuracy for predicting arrhythmic death varies between studies, possibly due to differences in the selection of the lead used for measurement of the QT interval. The purpose of this study was to analyze the prognostic accuracy of all known ways to select the lead. METHODS AND RESULTS Three institutions that used different methods for measuring QT intervals provided their QT databases. They included more than 3500 twelve-lead surface ECGs. The data represented low- and high-risk patients of the normal population (survivors vs dead from cardiovascular causes), acute myocardial infarction (survivors versus death from all causes) and remote myocardial infarction (with vs without a history of ventricular arrhythmia). The prognostic accuracy was defined as the area under the Receiver Operator Curve (ROC-area). The most accurate standard leads were I and aVL and the least accurate was AVR. The most accurate precordial lead was V4. The prognostic accuracy of the longest QT interval was higher than for any standard lead. The prognostic accuracy of the mean of the three longest QT intervals was equal to or slightly lower than for the longest QT interval. CONCLUSIONS The highest prognostic accuracy is obtained with the longest QT interval. The accuracies of the lead selection methods are so different that it can explain a substantial part of the differences between otherwise similar studies in the literature. We recommend the use of the mean value of the three longest QT intervals.
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Affiliation(s)
- Kaspar Lund
- Department of Cardiology, Skejby University Hospital, DK-8200 Aarhus N, Denmark.
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Uyarel H, Uslu N, Okmen E, Tartan Z, Kasikcioglu H, Dayi SU, Cam N. QT dispersion in sarcoidosis. Chest 2005; 128:2619-25. [PMID: 16236934 DOI: 10.1378/chest.128.4.2619] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
STUDY OBJECTIVES QT dispersion (QTd) is the maximal interlead difference in QT interval on surface 12-lead ECG. An increase in QTd is found in various cardiac diseases. Sarcoidosis augments inhomogeneity in ventricular repolarization by sarcoid granuloma, which significantly correlates with ventricular fibrillation. Changes in QTd in the course of sarcoidosis have not been investigated previously. DESIGN The study included 35 patients with systemic sarcoidosis. The diagnosis of systemic sarcoidosis was made by biopsy. Thallium scintigraphy was performed in all patients with systemic sarcoidosis. Cardiac sarcoidosis was diagnosed in 16 patients based on abnormal thallium scintigraphy and normal coronary arteriography results. QTd, corrected QTd (cQTd), maximum QT (QTmax), maximum corrected QT (cQTmax), minimum QT, and minimum corrected QT intervals were measured. Twenty-four healthy subjects represented the control group for QT interval analysis. MEASUREMENTS AND RESULTS In the cardiac sarcoidosis group, mean QTd (+/- SD) was significantly greater than in the noncardiac sarcoidosis group and control group (49.50 +/- 10.86 ms, 28.14 +/- 11.02 ms, and 27.08 +/- 10.41 ms, respectively; p < 0.001). cQTd was significantly greater in the cardiac sarcoidosis group than in the noncardiac sarcoidosis group and control group (53.17 +/- 10.44 ms, 30.61 +/- 10.94 ms, and 29.01 +/- 10.52 ms, respectively; p < 0.001). QTmax (440 +/- 15.01 ms, 409 +/- 14.86 ms, and 410 +/- 13.21 ms; p < 0.001) and cQTmax (449 +/- 16.31 ms, 417 +/- 12.51 ms, and 418 +/- 11.76, respectively; p < 0.001) were also significantly greater in patients with cardiac sarcoidosis. In a limited follow-up group (11 cardiac and 9 noncardiac sarcoidosis patients), the incidence of premature ventricular contraction (PVC) on ECG was greater in the cardiac sarcoidosis group than in the noncardiac sarcoidosis group (36% and 0%, respectively; p < 0.05). A medium correlation existed between QTd and PVC (r = 0.331, p < 0.05). CONCLUSIONS QTd, cQTd, QTmax, and cQTmax are prolonged in patients with cardiac sarcoidosis compared to the patients with noncardiac sarcoidosis and control subjects. The incidence of PVC on ECG was greater in the cardiac sarcoidosis group than in the noncardiac sarcoidosis group.
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Affiliation(s)
- Huseyin Uyarel
- Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey.
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Liang Y, Kongstad O, Luo J, Liao Q, Holm M, Olsson B, Yuan S. QT dispersion failed to estimate the global dispersion of ventricular repolarization measured using monophasic action potential mapping technique in swine and patients. J Electrocardiol 2005; 38:19-27. [PMID: 15660343 DOI: 10.1016/j.jelectrocard.2004.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of this study was to evaluate whether the QT dispersion measured from 12-lead electrocardiogram (ECG) can estimate the global dispersion of ventricular repolarization (DVR) measured using a monophasic action potential (MAP) mapping technique. Monophasic action potentials were recorded from 75 +/- 12 left ventricular sites in 10 pigs and from 48 +/- 16 left or right ventricular sites in 15 patients using the CARTO mapping system. The maximum DVRs in both end-of-repolarization and MAP duration among all the mapped sites were calculated and termed as global DVR for each measurement. QT intervals, QT peak and QT end , were measured from the 12-lead ECG, and QT dispersions; namely the differences between the maximum and the minimum of the QT peak and QT end were calculated. We found that QT dispersions were significantly smaller than (P < .05) and poorly correlated with the global DVRs both in pigs and patients. Bland-Altman agreement analysis demonstrated a marked variation of the differences and an obvious lack of agreement between the results obtained using the ECG and the MAP methods. In our patients, the global DVR increased markedly during ventricular tachycardia as compared with that during sinus rhythm (P < .05), whereas there was no significant difference in QT dispersion between these 2 subgroups. In conclusion, QT dispersion on the surface ECG could not estimate the global DVR measured using the MAP mapping technique. These findings are not consistent with some previously reported observations, suggesting the need for reappraisal of the electrophysiological implications of QT dispersion.
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Affiliation(s)
- Yanchun Liang
- Department of Cardiology, University Hospital, SE-221 85 Lund, Sweden
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Madias JE. QTc interval in patients with changing edematous states: implications on interpreting repeat QTc interval measurements in patients with anasarca of varying etiology and those undergoing hemodialysis. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2005; 28:54-61. [PMID: 15660804 DOI: 10.1111/j.1540-8159.2005.09384.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Associations have been described among weight, amplitude of QRS complexes, and QRS duration (QRSd) in patients with anasarca (AN), and changes in the amplitude of the QRS complexes, QRSd, and QTc after hemodialysis (HD) and in patients with heart failure with associated peripheral edema congestive heart failure. The objective of this study was to evaluate the hypothesis that changes in QTc in patients with AN and after HD are at least partially apparent, due to changing edematous states, and not totally due to altered electrophysiology. QTc was measured in patients with AN on admission, at peak weight (N = 28), and at their subsequent lowest weight (N = 12), in 28 control patients without change in weight during hospitalization, and in one patient before and after 26 HD sessions. In the patients with AN, the QTc was 451 +/- 36 ms on admission and dropped to 423 +/- 46 ms at peak weight (P = 0.005). QTc was 421 +/- 44 ms at peak weight and raised to 434 +/- 30 at subsequent lowest weight (P = 0.32). In the controls, QTc on admission and at discharge were 435 +/- 34 and 428 +/- 23 ms, correspondingly (P = 0.18). QTc increased from 472 +/- 18 ms before to 489 +/- 36 ms after HD (P = 0.017). Alterations in QTc in AN, or HD suggest that the changes in the QTc may be partially only apparent, and due to the electrocardiogram machine-based measurement of the attenuated/augmented QRST complexes resulting from fluid shifts.
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Affiliation(s)
- John E Madias
- Mount Sinai School of Medicine, New York University, New York, New York, USA.
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Vaidean GD, Schroeder EB, Whitsel EA, Prineas RJ, Chambless LE, Perhac JS, Heiss G, Rautaharju PM. Short-term repeatability of electrocardiographic spatial T-wave axis and QT interval. J Electrocardiol 2005; 38:139-47. [PMID: 15892024 DOI: 10.1016/j.jelectrocard.2004.09.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although ventricular repolarization abnormalities reflect arrhythmic susceptibility, few reliable tools exist to identify their presence. We investigated the repeatability of the spatial T-wave axis and QT interval from standard 12-lead electrocardiograms in 63 asymptomatic volunteers. Certified technicians used a standardized protocol to digitally record 2 electrocardiograms per participant at each of 2 visits separated by 1 to 2 weeks. Absolute paired differences within and between visits were 0.19 degrees and 0.90 degrees for the T-wave axis and 1.08 and 1.55 milliseconds for the QT interval, respectively. The intraclass correlation coefficients for the T-wave axis and QT interval were 0.87 and 0.86, respectively. The impact of repeated measurements on the precision of the QT-interval measurements was evaluated for a hypothetical clinical trial aimed at detecting a drug-induced QT prolongation. We conclude that the spatial T-wave axis is as repeatable a measure of ventricular repolarization as the QT interval.
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Affiliation(s)
- Georgeta D Vaidean
- Department of Medicine, University of North Carolina schools of Public Health and Medicine, Chapel Hill, NC 27514, USA.
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Sheehan J, Perry IJ, Reilly M, Salim A, Collins M, Twomey EM, Daly A, Loingsigh SN, Elwood P, Ben-Shlomo Y, Davey-Smith G. QT dispersion, QT maximum and risk of cardiac death in the Caerphilly Heart Study. ACTA ACUST UNITED AC 2004; 11:63-8. [PMID: 15167208 DOI: 10.1097/01.hjr.0000114970.39211.9e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND It has been postulated that increased inter-lead differences in QT interval (QT dispersion) and the maximum QT interval (QTmax), in the standard 12-lead electrocardiogram (ECG), may be associated with an increased risk of cardiac death. The aims of this study were to assess the relationship between QT dispersion and QTmax, corrected and uncorrected for heart rate, and the risk of cardiac death. DESIGN Nested case-control study within the Caerphilly prospective cohort study. METHODS We studied 2512 men who participated in phase 1 of the Caerphilly study between 1979 and 1983. After a mean follow up of 7.1 years, 218 men had died from coronary heart disease and these men were compared with 218 age-matched controls. RESULTS Data are presented on 422 patients with ECG suitable for analysis, 207 cases and 215 controls. Four trained observers measured the QT intervals and the reliability of each observer was estimated using repeat measurements on a randomly chosen sub-sample of ECGs. Median corrected QT dispersion and corrected QTmax were significantly higher in cases than in controls (51.9 versus 47.7 ms [P=0.01] and 430 versus 421 ms [P<0.001] respectively). In univariate analyses by quartiles of corrected QT dispersion and corrected QTmax, increased risk was largely confined to the upper quartile of the distribution with these subjects having twice the risk of those in the lower quartile [odds ratio (OR) 2.14, 95% confidence interval (CI) 1.2-3.7 and 2.56 (95% CI 1.5-4.5) respectively]. In logistic regression analysis, adjusted for age, smoking, body mass index, hypertension, history of myocardial infarction and ECG Minnesota code, we observed an increased risk in the upper quartile of the corrected QT dispersion relative to the other three quartiles combined [adjusted OR=1.74 (P=0.03)]. The magnitude of this association was increased in analyses based on the data from the most reliable observers. The association between corrected QTmax and cardiac death was attenuated in multivariate analysis. The findings in relation to both uncorrected QT dispersion and uncorrected QTmax were similar, i.e., consistent with a significant independent effect of QT dispersion but not QTmax for cardiac death in multivariate analysis. CONCLUSION The data suggest that QT dispersion is an independent predictor of cardiac death provided it can be measured with sufficient reliability. The association is non-linear with increased risk largely confined to the upper quartile of the distribution. The QT maximum is not an independent predictor of cardiac death.
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Affiliation(s)
- John Sheehan
- Department of Epidemiology and Public Health, University College Cork, Ireland
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Pastore CA, Arcêncio SR, Tobias NMMO, Kaiser E, Filho MM, Moreira LFP, Stolf NA, Bocchi E, Ramires JAF. QT interval dispersion analysis in patients undergoing left partial ventriculectomy (Batista operation). Ann Noninvasive Electrocardiol 2004; 9:375-82. [PMID: 15485517 PMCID: PMC6932263 DOI: 10.1111/j.1542-474x.2004.94582.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND QT interval dispersion (QTd) has been valued as a marker of increased vulnerability for cardiac arrhythmias. QTd was analyzed in patients undergoing the left partial ventriculectomy (LPV) or Batista operation, a palliative surgery for patients in the line for heart transplantation, which is associated with complex arrhythmia and death from sustained ventricular tachyarrhythmia (SVT). METHODS Pre- and postoperative R-R, QT, QTc, JT (QT - QRS), and aT (apex to end of T wave) intervals were obtained by 87-lead body surface mapping from 24 patients (18 male), mean age 46.4 +/- 9.15 years. Dispersions of QT, QTc, JT, and aT intervals were calculated, and the total number of arrhythmic events were assessed, aiming to verify a possible risk predictor for the occurrence of SVTs. Subgroups of patients who survived and who died after LPV were also compared, aiming to obtain a QTd cutoff value that could be used prognostically. RESULTS No difference between pre- and postoperative mean values were found, but a very significant difference was seen when comparing QTd and QTcD values for surviving and dead patients: QTd, cutoff value was 95 ms, while QTcD value was 114 ms. CONCLUSION There were no significant differences between pre- and postoperative variables or the number of arrhythmic events, but there were significant differences between both pre- and postoperative QTd and QTcD data from surviving and dead patients; this enabled the determination of cutoff values that we believe may be useful for the prognosis of the LPV outcome.
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Affiliation(s)
- Carlos Alberto Pastore
- Heart Institute (InCor) of the University of São Paulo Medical School, São Paulo, Brazil.
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Sakamoto S, Tambara K, Kambara N, Miyamoto S, Tsukamoto T, Fujita M. Right lateral decubitus position reduces QT dispersion in patients with chronic heart failure. J Electrocardiol 2004; 37:201-6. [PMID: 15286933 DOI: 10.1016/j.jelectrocard.2004.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A greater QT dispersion in patients with chronic heart failure (CHF) appears to be a non-invasive marker of susceptibility to malignant ventricular arrhythmias. We evaluated whether QT dispersion in CHF patients is modified by the patients' recumbent position. In 12 CHF patients, and age and sex-matched 12 normal subjects, a single 12-lead surface ECG was recorded in each postural position [left lateral decubitus position (L), supine position (S), and right lateral decubitus position (R)]. In normal subjects, the QT dispersion was comparable in the three recumbent positions [L: 47+/-15 (SD) ms, S: 40+/-9 ms, R: 38+/-14 ms, P=NS]. In contrast, in CHF patients, QT dispersion was significantly shorter in R than those in L and S (L: 93+/-42 ms*, S: 81+/-29 ms*, R: 63+/-24 ms, *P <.05 vs. R). In conclusion, reclining in R reduces the prolonged QT dispersion in CHF patients.
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Affiliation(s)
- Satoko Sakamoto
- School of Health Sciences, Faculty of Medicine, Kyoto University, Kyoto, Japan
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Anderson KJ, Sear JW. QTc dispersion is prolonged in patients with early postoperative adverse cardiovascular events and those with silent myocardial ischemia. J Cardiothorac Vasc Anesth 2004; 18:281-7. [PMID: 15232806 DOI: 10.1053/j.jvca.2004.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To determine if increased QT interval dispersion (corrected and not corrected for heart rate) is associated with perioperative silent myocardial ischemia or postoperative adverse cardiovascular events. DESIGN Blinded retrospective observational study. SETTING University hospital. PARTICIPANTS One hundred eighty-one perioperative patients receiving general anesthesia for elective major vascular or orthopedic surgery. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS QT dispersion, corrected and uncorrected for heart rate, was prolonged in patients suffering significant myocardial ischemia up to 48 hours assessed by Holter ECG monitoring, for early cardiac morbidity and all early cardiac events (including mortality) up to 1 month postoperatively. There were no significant changes in patients showing early cardiovascular mortality or late cardiac morbidity or mortality between 1 and 12 months postoperatively. Morbidity and mortality were determined from clinical notes, laboratory investigations, and autopsy when available. QT dispersion performed poorly as a screening test to identify those who subsequently developed early adverse cardiovascular outcomes. CONCLUSIONS QT dispersion is prolonged in those at risk of early adverse cardiovascular events but is a poor screening tool.
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Affiliation(s)
- Keith J Anderson
- Nuffield Department of Anaesthetics, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
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Ilkay E, Yavuzkir M, Karaca I, Akbulut M, Pekdemir M, Aslan N. The effect of ST resolution on QT dispersion after interventional treatment in acute myocardial infarction. Clin Cardiol 2004; 27:159-62. [PMID: 15049385 PMCID: PMC6654344 DOI: 10.1002/clc.4960270313] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND It has been reported that reperfusion treatment reduces QT dispersion (QTD) in cases of acute myocardial infarction (AMI). Successful myocardial perfusion is not synonymous with Thrombolysis in Myocardial Infarction (TIMI) III flow. It has been demonstrated that in AMI, the grade of ST-resolution correlates strongly with left ventricular (LV) function, enzyme elevation, and mortality after primary angioplasty. HYPOTHESIS This study investigated the relation between ST-resolution grade and QTD and the feasibility of using QTD as a determinant of successful myocardial tissue perfusion in patients in whom TIMI III flow in the infarct-related artery (IRA) is restored by interventional treatment for AMI. METHODS The study included 57 patients (38 men, 19 women, average age 54.4 +/- 11.6 years), whose IRA was perfused by primary angioplasty after the diagnosis of anterior AMI with ST elevation. Electrocardiograms of patients were taken 45 +/- 12 min post procedure, and patients were divided into three groups depending on the grade of ST resolution: Group 1, full ST resolution; Group 2, partial ST resolution; and Group 3, unsuccessful ST resolution. RESULTS Full ST resolution was seen in 19 cases (33%), partial resolution in 26 cases (47%), and unsuccessful resolution in 12 cases (20%). There were no differences among groups in terms of risk factors, stent diameters, symptom onset-balloon time, LV function, and preprocedure corrected QTD (QTcD) (p = 0.274). After the procedure, a significant reduction in QTcD was found within the groups (p = 0.0001 in Group 1, p = 0.004 in Group 2, and p = 0.011 in Group 3). Reductions in QTcD post procedure were 24.21 +/- 14.27, 11.85 +/- 16.18, and 12.50 +/- 11.58 ms in Groups 1, 2, and 3, respectively. There was a statistically significant difference of p = 0.015 between Groups 1 and 2 and a difference of p = 0.028 between Groups 1 and 3. There was no statistically significant difference between Groups 2 and 3 (p = 0.916). CONCLUSION In acute MI, TIMI III flow led to a reduction in QTcD, and full myocardial perfusion made an additional contribution to the electrical stability of the myocardium.
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Affiliation(s)
- Erdoğan Ilkay
- Department of Cardiology, Firat University, School of Medicine, Elaziğ, Turkey.
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Okin PM. QT interval prolongation and prognosis: further validation of the quantitative approach to electrocardiography**Editorials published in the Journal of the American College of Cardiologyreflect the views of the authors and do not necessarily represent the views of JACCor the American College of Cardiology. J Am Coll Cardiol 2004; 43:572-5. [PMID: 14975465 DOI: 10.1016/j.jacc.2003.11.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Corović N, Duraković Z, Misigoj-Duraković M. Dispersion of the corrected QT interval in the electrocardiogram of the ex-prisoners of war. Int J Cardiol 2003; 88:279-83. [PMID: 12714208 DOI: 10.1016/s0167-5273(02)00392-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The study of electrocardiograms (ECGs) was performed in a subgroup of 181 men, ex-prisoners of war with mean age 35.8+/-11.0 years and mean duration of imprisonment 164.5+/-87.1 days, chosen at random from the total sample of released prisoners (N=1458). The control group was pair-matched. The analysis of ECGs was done according to the Minnesota code, and Bazett's formula gave the values of the corrected QT interval (QT(c)). The dispersion of the QT(c) interval is determined by the difference between the longest and the shortest measured QT(c) interval in each ECG lead. The results of descriptive statistics in the group of ex-prisoners showed the range of QT(c) dispersion of 8.0-122.0 ms (mean 52.4+/-21.6 ms), while in the control group the range was 6.0-72.0 ms (mean 30.4+/-13.8 ms) (df=360, t=11.536; P<0.001). The QT(c) interval from 422.0 to 480.0 ms had 60.2% ex-prisoners and 30.4% controls, while a QT(c) interval over 480.0 ms had 19.3% ex-prisoners and 1.10% controls (P<0.0001). In the ex-prisoners group, the QT(c) dispersion over 50 ms was present in 51.4%; of those, a dispersion of 95 ms and more was found in 3.9%, while in the controls a QT(c) dispersion over 50 ms was found in 8.3%, but a dispersion of 95 ms and more was not recorded (P<0.0001). The odds ratio estimated for the prolonged QT(c) interval was 8.467 and for enlarged QT(c) dispersion it was 11.695 in the ex-prisoners versus controls (P<0.001). In conclusion, persons exposed to long-term maltreatment in detention camps have significantly greater QT(c) dispersion, as well as a higher relative risk of prolonged QT(c) interval and greater QT(c) dispersion than a control group.
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Affiliation(s)
- Naima Corović
- Institute for Medical Research and Occupational Health, Zagreb, Croatia.
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Carluccio E, Biagioli P, Bentivoglio M, Mariotti M, Politano M, Savino K, Sardone M, Locati EH, Ambrosio G. Effects of acute myocardial ischemia on QT dispersion by dipyridamole stress echocardiography. Am J Cardiol 2003; 91:385-90. [PMID: 12586249 DOI: 10.1016/s0002-9149(02)03230-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Increased dispersion of the QT interval has been observed during pacing or exercise stress testing in patients with coronary artery disease (CAD). It has not been established whether this phenomenon is a consequence of ischemia. Therefore, we sought to evaluate whether dipyridamole-induced myocardial ischemia, as directly detected by echocardiographic monitoring of regional contractile function, would affect QT dispersion. Twenty-four patients with nonsignificant and 34 patients with significant CAD but no previous myocardial infarction underwent dipyridamole stress echocardiography while not taking medications. QT dispersion was measured on a 12-lead electrocardiogram at baseline and at various times after dipyridamole infusion. Dipyridamole infusion did not influence QT dispersion in patients without CAD. QT dispersion was similarly unaffected in patients with CAD in whom dipyridamole did not induce wall motion abnormalities. In contrast, in patients with positive dipyridamole stress test findings, QT dispersion increased from 60 +/- 17 ms at baseline to 94 +/- 25 ms during peak infusion (p <0.0001), with a time course mirroring that of development of contractile abnormalities. QT dispersion returned to 63 +/- 25 ms upon relief of ischemia by administration of aminophylline. The increase in QT dispersion was significantly related to the extent of contractile dysfunction induced by dipyridamole. Although ST-segment depression occurred in only 40% of patients with positive dipyridamole stress test findings, 88% of such patients had an increase in QT dispersion. Analysis of the receiver-operating characteristic curve showed that a QT dispersion increase of > or =20 ms identified positive findings for dipyridamole stress echocardiography with 68% sensitivity and 91% specificity. Thus, QT dispersion is acutely affected by myocardial ischemia induced by the administration of dipyridamole. Measurement of QT dispersion may improve detection of stress-induced ischemia on surface electrocardiograms.
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Affiliation(s)
- Erberto Carluccio
- Division of Cardiology, University of Perugia School of Medicine, Perugia, Italy
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41
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Kesek M, Jernberg T, Lindahl B, Englund A. QT dispersion measured by an automatic continuous method early in patients admitted for chest pain. Int J Cardiol 2002; 85:217-24; discussion 225-7. [PMID: 12208586 DOI: 10.1016/s0167-5273(02)00158-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND There is a need for risk markers in patients with acute chest pain. QT dispersion (QTd) is a prognostic marker in several groups of patients. A problem with the manual measurement of QTd is operator dependency. This can be avoided by using an automatic method. We investigated QTd, derived from multiple automatic measurements, as a risk marker in a population with chest pain. METHODS In 548 patients admitted to the coronary care unit for chest pain and nondiagnostic ECG, 12-lead ECG recordings were collected each minute during the initial 17 h. From recordings with > or =10 valid leads, mean QTd (QTdMean), QTd in the first satisfactory recording and estimates of variability of QTd were computed and correlated to outcome. RESULTS In the group with QTdMean > or =40 ms (n=277), 10 patients died during the initial 30 days; one patient died in the group with QTdMean <40 ms (n=271) (P=0.07). During follow-up (median 6 months), 19 vs. five patients died in each group (P=0.03). The figures for the triple endpoint death/myocardial infarction/revascularisation were 52 vs. 27 events during the initial 30 days (P=0.018) and 76 vs. 41 events during follow-up (P=0.003). QTd in the first recording did not predict new cardiac events. CONCLUSIONS QTd measured as the mean value of multiple recordings was found to be a powerful marker for cardiac events during follow-up. It was superior to the analysis of QTd in a single ECG. It can be used for the selection of low-risk patients, but was not effective in identifying high-risk patients.
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Affiliation(s)
- Milos Kesek
- Department of Cardiology, Akademiska Hospital, 751 85 Uppsala, Sweden.
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Jouven X, Hagege A, Charron P, Carrier L, Dubourg O, Langlard JM, Aliaga S, Bouhour JB, Schwartz K, Desnos M, Komajda M. Relation between QT duration and maximal wall thickness in familial hypertrophic cardiomyopathy. Heart 2002; 88:153-7. [PMID: 12117842 PMCID: PMC1767224 DOI: 10.1136/heart.88.2.153] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND QT abnormalities have been reported in left ventricular hypertrophy and hypertrophic cardiomyopathy. OBJECTIVE To determine the relation between left ventricular hypertrophy and increased QT interval in familial hypertrophic cardiomyopathy. METHODS The QT interval was measured in 206 genotyped adult subjects with familial hypertrophic cardiomyopathy from 15 unrelated families carrying mutations in the beta myosin heavy chain (beta-MHC) gene (five families, n = 68) or the cardiac myosin binding protein C (MyBPC) gene (10 families, n = 138). Subjects were classified as genetically unaffected (controls, n = 112), affected with left ventricular hypertrophy (penetrants, n = 58), or affected without left ventricular hypertrophy (non-penetrants, n = 36). RESULTS There was a significant increase in QTmax and QTmin from controls to non-penetrants and penetrants for both the MyBPC group (p < or = 0.001 and p < or = 0.001, respectively) and the beta-MHC group (p < or = 0.001 and p < or = 0.001, respectively). In the MyBPC group, the increase in the QT interval could be explained by increased left ventricular hypertrophy. In the beta-MHC group, non-penetrants had a significantly longer QTmax than controls despite the absence of left ventricular hypertrophy, and a similar QT interval to penetrants despite a lesser degree of left ventricular hypertrophy. CONCLUSIONS In familial hypertrophic cardiomyopathy, genetically affected subjects without left ventricular hypertrophy may have a prolonged QT duration, which depends not only on the degree of left ventricular hypertrophy, when present, but also on the causative mutation.
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Affiliation(s)
- X Jouven
- Service de Cardiologie, Hôpital Européen Georges Pompidou, Paris, France.
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Beaubien ER, Pylypchuk GB, Akhtar J, Biem HJ. Value of corrected QT interval dispersion in identifying patients initiating dialysis at increased risk of total and cardiovascular mortality. Am J Kidney Dis 2002; 39:834-42. [PMID: 11920351 DOI: 10.1053/ajkd.2002.32005] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cardiovascular disease remains the most common cause of premature death in end-stage renal disease (ESRD). Although several predictors of cardiac death have been reported, identifying individuals most at risk remains difficult. Previous studies in nonuremic populations have associated cardiac mortality, in particular sudden death, with increased QT dispersion (QTd); defined as the difference between the maximal and minimal QT interval on a standard electrocardiogram. The present study aimed to determine the prognostic value of QTd and corrected QTd (QTdc) in predicting total, cardiovascular, and arrhythmia-related mortality in ESRD patients initiating dialysis. The study was a retrospective cohort of adult ESRD patients starting peritoneal dialysis or hemodialysis between 1990 and 1994. Statistical analysis was by Cox proportional hazard modeling and Kaplan-Meier analysis. Primary study endpoints were total, cardiovascular, and arrhythmia-related mortality. Nonfatal cardiovascular events were a secondary endpoint. A total of 147 patients were studied for a period of 5 to 9 years. In Cox modeling, QTdc was an independent predictor of total (relative risk [RR] = 1.53; difference for RR = 50 msec; P = 0.0001) and cardiovascular mortality (RR = 1.57; difference for RR = 50 msec; P = 0.028) and trended toward arrhythmia-related mortality (P = 0.061). Total mortality also was predicted independently by lack of renal transplantation, radiographic cardiomegaly, and predialysis serum albumin. In multivariate analysis, QTdc was associated weakly with serum calcium, mean QT interval, and presence of diabetes mellitus. QTdc may be a useful marker for identifying dialysis patients at an increased risk for overall and cardiovascular mortality.
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Affiliation(s)
- Eliot R Beaubien
- Division of Nephrology, McGill University, Montreal, Quebec, Canada.
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Brendorp B, Elming H, Jun L, Køber L, Torp-Pedersen C. Effect of dofetilide on QT dispersion and the prognostic implications of changes in QT dispersion for patients with congestive heart failure. Eur J Heart Fail 2002; 4:201-6. [PMID: 11959050 DOI: 10.1016/s1388-9842(01)00235-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
AIMS Drug-induced changes in QT dispersion may be a way of detecting harmful repolarisation abnormalities for patients receiving antiarrhythmic drugs affecting ventricular repolarisation. METHODS AND RESULTS In 463 congestive heart failure (CHF) patients enrolled in the Danish Investigations Of Arrhythmia and Mortality On Dofetilide-CHF (DIAMOND-CHF) study, both pre-treatment and on-treatment day 2-6 QT dispersion was available from standard 12-lead ECGs. Patients were randomised in a double-blind manner to receive either placebo or dofetilide, a new class III antiarrhythmic drug. During a median follow-up of 19 months (minimum 1 year), 179 patients (39%) died (135 patients from cardiac causes). Changes in QT dispersion did not predict all-cause or cardiac mortality for patients treated with dofetilide in multivariate survival analysis (Risk ratio: 1.02, 95% confidence interval: 0.97-1.08, P>0.4). This finding was independent of pre-treatment QT dispersion. Dofetilide caused a small QT dispersion increment of 8 ms, not different from the changes seen in the placebo group (3 ms). CONCLUSION For patients with CHF and reduced left ventricular systolic function, changes in QT dispersion following treatment with dofetilide do not predict all-cause or cardiac mortality. The dofetilide-induced QT dispersion changes are small and comparable to those seen in placebo treated patients.
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Affiliation(s)
- Bente Brendorp
- Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark.
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Malik M, Camm AJ. Evaluation of drug-induced QT interval prolongation: implications for drug approval and labelling. Drug Saf 2001; 24:323-51. [PMID: 11419561 DOI: 10.2165/00002018-200124050-00001] [Citation(s) in RCA: 196] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Assessment of proarrhythmic toxicity of newly developed drugs attracts significant attention from drug developers and regulatory agencies. Although no guidelines exist for such assessment, the present experience allows several key suggestions to be made and an appropriate technology to be proposed. Several different in vitro and in vitro preclinical models exist that, in many instances, correctly predict the clinical outcome. However, the correspondence between different preclinical models is not absolute. None of the available models has been demonstrated to be more predictive and/or superior to others. Generally, compounds that do not generate any adverse preclinical signal are less likely to lead to cardiac toxicity in humans. Nevertheless, differences in likelihood offer no guarantee compared with entities with a preclinical signal. Thus, the preclinical investigations lead to probabilistic answers with the possibility of both false positive and false negative findings. Clinical assessment of drug-induced QT interval prolongation is crucially dependent on the quality of electrocardiographic data and the appropriateness of electrocardiographic analyses. An integral part of this is a precise heart rate correction of QT interval, which has been shown to require the assessment of QT/RR relationship in each study individual. The numbers of electrocardiograms required for such an assessment are larger than usually obtained in pharmacokinetic studies. Thus, cardiac safety considerations need to be an integral part of early phase I/II studies. Once proarrhythmic safety has been established in phase I/II studies, large phase III studies and postmarketing surveillance can be limited to less strict designs. The incidence of torsade de pointes tachycardia varies from 1 to 5% with clearly proarrhythmic drugs (e.g. quinidine) to 1 in hundreds of thousands with drugs that are still considered unsafe (e.g. terfenadine, cisapride). Thus, not recording any torsade de pointes tachycardia during large phase III studies offers no guarantee, and the clinical premarketing evaluation has to rely on the assessment of QT interval changes. However, since QT interval prolongation is only an indirect surrogate of predisposition to the induction of torsade de pointes tachycardia, any conclusion that a drug is safe should be reserved until postmarketing surveillance data are reviewed. The area of drug-related cardiac proarrhythmic toxicity is fast evolving. The academic perspective includes identification of markers more focused compared with simple QT interval measurement, as well as identification of individuals with an increased risk of torsade de pointes. The regulatory perspective includes careful adaptation of new research findings.
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Affiliation(s)
- M Malik
- Department of Cardiological Sciences, St George's Hospital Medical School, London, England.
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Spier AW, Meurs KM, Muir WW, Lehmkuhl LB, Hamlin RL. Correlation of QT dispersion with indices used to evaluate the severity of familial ventricular arrhythmias in Boxers. Am J Vet Res 2001; 62:1481-5. [PMID: 11560281 DOI: 10.2460/ajvr.2001.62.1481] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To measure QT interval duration and QT dispersion in Boxers and to determine whether QT variables correlate with indices of disease severity in Boxers with familial ventricular arrhythmias, including the number of ventricular premature complexes per day, arrhythmia grade, and fractional shortening. ANIMALS 25 Boxers were evaluated by ECG and echocardiography. PROCEDURE The QT interval duration was measured from 12-lead ECG and corrected for heart rate (QTc), using Fridericia's formula. The QT and QTc were calculated for each lead, from which QT and QTc dispersion were determined. Echocardiography and 24-hour ambulatory ECG were performed to evaluate for familial ventricular arrhythmias. Total number of ventricular premature complexes, arrhythmia grade, and fractional shortening were determined and used as indices of disease severity. RESULTS There was no correlation between any QT variable and total number of ventricular premature complexes, arrhythmia grade, or fractional shortening. No difference between QT dispersion and QTc dispersion was identified, and correction for heart rate did not affect the results. CONCLUSIONS AND CLINICAL RELEVANCE QT interval duration and dispersion did not correlate with indices of disease severity for familial ventricular arrhythmias. Heart rate correction of the QT interval did not appear to be necessary for QT dispersion calculation in this group of dogs. QT dispersion does not appear to be a useful noninvasive diagnostic tool in the evaluation of familial ventricular arrhythmias of Boxers. Identification of affected individuals at risk for sudden death remains a challenge in the management of this disease.
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Affiliation(s)
- A W Spier
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus 43210, USA
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Abstract
Twenty elderly patients (12 females and 8 males, aged 65-88 years) were treated because of hypothermia: 11 suffered from moderate (35-32 degrees C) and nine from severe hypothermia (<32 degrees C). The control group consisted of 20 age and sex-matched healthy elderly persons. Twelve-channel electrocardiograms were recorded on admission and during hospitalization. In patients with moderate hypothermia Osborn wave was present in eight of 11, and minimal Osborn wave in three of 11; in severe hypothermia Osborn wave was seen in seven of nine, and minimal in two of nine. The corrected Q-T interval (Q-Tc) was analyzed according to the formula of Bazett: measured Q-T(s)/ radical R-R(s). The JT and the corrected JT interval (JTc) were measured according to the formula: JT=Q-T-QRS. The Q-T interval index (Q-TI) was measured according to the formula: (Q-TI:656)x(HR+100); and the JT interval index JTI: (JT:518)x(HR+100). The dispersion of the Q-Tc (JTc) was defined as the difference between maximum and minimum measured Q-Tc interval (JTc). The Q-Tc interval in the group with hypothermia was 651.41+/-130.06 ms, while in the control group it was 398.14+/-76.21 ms (P<0.001). The Q-Tc dispersion in the group with hypothermia was 91.39+/-51.98, and in the control group 33.21+/-10.25 ms (P<0.001). The Q-TcI in the group with hypothermia was 89.91+/-21.44, and in the control group 39.56+/-9.41 ms ((P<0.001). The JTc in the group with hypothermia was 542.66+/-132.74, in the control group: 328.06+/-76.92 (P<0.001). The JTc dispersion in the group with hypothermia was 79.35+/-46.22, and in the control group 28.53+/-7.99 (P<0.0001). The JTcI in the group with hypothermia was 93.06+/-17.38, in the control group it was 40.23+/-7.59 (P<0.001). The mean values of the Q-TcI were greater than Q-TI, and the mean values of the JTcI were greater than JTI, but the difference was not significant (P>0.10). The mean values of the JTcI were greater than Q-TcI, but the difference was not significant as well (P>0.05). There was no correlation between rectal temperature and dispersion of Q-T, Q-Tc, JT, JTc, and Osborn wave. The maximum Osborn wave and the maximum Q-T interval were registered in anteroseptal leads (V(2)-V(3)). The dispersion of the Q-Tc and of the JTc lasted more than Osborn wave. There was no correlation between rectal temperature and PR interval, RR interval and QRS duration. The prolonged dispersion of the Q-Tc (and JTc) last 24-48 h longer than Osborn wave.
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Affiliation(s)
- Z Duraković
- Department of Internal Medicine, Rebro University Hospital, School of Medicine, Zagreb, Croatia
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48
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Bodí V, Sanchis J, Navarro A, Plancha E, Chorro FJ, Berenguer A, Insa L, Escriche P, Cabadés F, Llácer A. QT dispersion within the first 6 months after an acute myocardial infarction: relationship with systolic function, left ventricular volumes, infarct related artery status and clinical outcome. Int J Cardiol 2001; 80:37-45. [PMID: 11532545 DOI: 10.1016/s0167-5273(01)00452-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION We analysed QT dispersion within the first 6 months postinfarction, its relationship with the main established risk stratifiers and its clinical value. METHODS AND RESULTS In 55 patients with a first Q-wave myocardial infarction the 12-lead electrocardiogram was scanned and digitised for analysis of QT dispersion (QT maximum-QT minimum) at first day (72 [61-96] ms), first week (69 [47-90] ms), first month (67 [46-88] ms) and sixth month (47 [40-74] ms; P<0.0001 vs. first day). Cardiac catheterization was performed at first week and at sixth month; QT dispersion was not related to ejection fraction, left ventricular volumes, infarct related artery status or contractile reserve (improvement of the infarcted area with low-dose dobutamine); no relation was found between QT dispersion decrease from first week to sixth month with regional systolic function improvement. Finally, during a mean follow-up period of 35+/-22 months QT dispersion was not independently related to clinical events. CONCLUSION QT dispersion decreases progressively during the first months after myocardial infarction. These changes should be taken into account to define cut-off values of clinical interest in this phase. This variable does not seem related to the classic prognosis predictors. In a nonselected postinfarction population it has a low clinical value.
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Affiliation(s)
- V Bodí
- Cardiology Unit, Internal Medicine Department, Hospital Comarcal. Avda. Gil de Atroncillo s/n. 12500, Vinaròs, Spain.
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49
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Brendorp B, Elming H, Jun L, Køber L, Malik M, Jensen GB, Torp-Pedersen C. Qt dispersion has no prognostic information for patients with advanced congestive heart failure and reduced left ventricular systolic function. Circulation 2001; 103:831-5. [PMID: 11171791 DOI: 10.1161/01.cir.103.6.831] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND QT dispersion is a potential prognostic marker of tachyarrhythmic events and death, but it is unclear whether this applies to patients with congestive heart failure (CHF). METHODS AND RESULTS Of the 1518 patients with advanced CHF and left ventricular dysfunction enrolled in the Danish Investigations of Arrhythmia and Mortality on Dofetilide-CHF (Diamond-CHF) study, a baseline ECG was available in 1319 patients. Of these, QT dispersion could be measured in 703 patients. During a median follow-up of 18 months (minimum 1 year), 285 patients (41%) died. The median QT dispersion was 70 ms (34/155 ms [5%/95% percentiles]), with no difference between survivors and nonsurvivors. Survival analysis revealed no prognostic information derived from QT dispersion regarding all-cause mortality (risk ratio 1.00, 95% CI 1.00 to 1.00; P=0.74), cardiac mortality (risk ratio 1.00, 95% CI 1.00 to 1.01; P=0.55), or cardiac arrhythmic mortality (risk ratio 1.00, 95% CI 0.99 to 1.01; P=0.38). CONCLUSIONS QT dispersion has no prognostic value regarding all-cause mortality, cardiac mortality, or cardiac arrhythmic mortality for patients with advanced CHF and reduced left ventricular systolic function.
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Affiliation(s)
- B Brendorp
- Copenhagen University Hospital, Gentofte, Denmark
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50
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Lee KW, Kligfield P, Dower GE, Okin PM. QT dispersion, T-wave projection, and heterogeneity of repolarization in patients with coronary artery disease. Am J Cardiol 2001; 87:148-51. [PMID: 11152829 DOI: 10.1016/s0002-9149(00)01306-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The clinically useful prognostic value of precordial QT dispersion in patients with heart disease is generally attributed to its measurement of regional heterogeneity of ventricular repolarization. However, when repolarization is abnormal, differences in measured QT intervals might result simply from variation in projection of the T-wave loop. To provide insight into the mechanism of QT dispersion, we used an analog device to transform conventional 12-lead electrocardiograms (ECGs) of 78 patients to derived 12-lead ECGs based on the heart vector. Because the electrical activity of the heart is represented by a single dipole, all QT dispersion in the transformed ECGs results from variation in projection of the T-wave loop and cannot be due to local heterogeneity of repolarization. Measured as the difference between the longest and shortest precordial QT intervals, QT dispersion in the derived ECGs, with no local heterogeneity of repolarization, was 53 +/- 49 ms (mean +/- SD). QT dispersion in these derived ECGs was similar in magnitude to that measured from the original standard 12-lead ECGs in these patients (49 +/- 23 ms, p = NS). Therefore, the precordial QT dispersion measured from standard ECGs of patients with coronary artery disease can be explained by interlead variation in precordial projection of the T-wave loop. Although regional heterogeneity might still contribute to precordial repolarization findings and to prognosis, this is not required to explain the QT dispersion observed in patients with coronary artery disease. Therefore, QT interval dispersion is not equivalent to heterogeneity of repolarization.
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Affiliation(s)
- K W Lee
- Department of Medicine, New York-Weill-Cornell Center of New York-Presbyterian Hospital, New York 10021, USA
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