Influence of Lead Selection and Population on Automated Measurement of QT Dispersion

Macfarlane, Peter W.; McLaughlin, S C; Rodger, J C

doi:10.1161/01.cir.98.20.2160

Cited by 131 publications

(85 citation statements)

References 43 publications

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“…QT d is significantly different between patients with a wide and a narrow T-wave loop, and a correspondence has been observed between QT d and the T-wave loop morphology (Kors et al 1999) rather than with VRD. In addition, similar QT d values have been measured on the standard 12-lead ECG and on synthesized 12 leads from the orthogonal XYZ leads, which intrinsically leave out regional repolarization heterogeneity (Macfarlane et al 1998). As a result, this QT d concept has been largely abandoned as a marker of VRD.…”

Section: (A ) Dispersion Of Repolarization Reflected On Ecg Intervalsmentioning

confidence: 89%

Cardiac repolarization analysis using the surface electrocardiogram

Pueyo

Martínez

Laguna

2008

Phil. Trans. R. Soc. A.

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Sudden cardiac death (SCD) is a challenging health problem in the western world. Analysis of cardiac repolarization from the electrocardiogram (ECG) provides valuable information for stratifying patients according to their risk of suffering from arrhythmic events that could end in SCD, as well as for assessing efficacy of antiarrhythmic therapies. In this paper, we start by exploring the cellular basis of ECG repolarization waveforms under both normal and pathological conditions. We then describe basic preprocessing steps that need to be accomplished on the ECG signal before extracting repolarization indices. A comprehensive review of techniques aimed to characterize spatial or temporal repolarization dispersion is provided, together with a summary of their usefulness for clinical risk stratification. Techniques that describe spatial dispersion of repolarization are based on either differences in repolarization duration or T-wave loop morphology. Techniques that evaluate temporal dispersion of repolarization include the analysis of QT interval adaptation to heart rate changes, QT interval and T-wave variability, and T-wave alternans.

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Section: (A ) Dispersion Of Repolarization Reflected On Ecg Intervalsmentioning

confidence: 89%

Cardiac repolarization analysis using the surface electrocardiogram

Pueyo

Martínez

Laguna

2008

Phil. Trans. R. Soc. A.

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“…When analyzing according to gender GF and GM groups had similar QTd levels. Reports show either no statistically significant difference in QTd between the genders (34). Compared to the GS and control subgroups, the GF group had significantly lower QTd than the CM group.…”

Section: Comparison Of Pd Qtd and Hr Values Between Gs And Control Gmentioning

confidence: 93%

The effect of Gilbert’s syndrome on the dispersions of QT and P-wave dispersion: an observational study

Cüre¹,

Yüce²,

Çiçek³

et al. 2013

Anadolu Kardiyol Derg

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Objective: Gilbert's syndrome (GS) decreases the incidence of atherosclerotic heart disease. The aim of the study was to evaluate whether the arrhythmia risk markers such as P-wave dispersion (Pd), QT dispersion (QTd) are reduced in patients with GS compared with healthy subjects. Methods: Sixty-one patients diagnosed with GS (31 females, 30 males) who had applied to the internal medicine outpatient clinic in the hospital were included in this cross-sectional, observational study. A control group of 61 healthy persons (31 females, 30 males), who were non-smokers and drinkers, were included. Both groups were between 16-45 years old. Results of anthropometric measurements, laboratory assays and electrocardiographic findings were recorded for each participant. Independent sample t-test and nested ANOVA were used for data analysis. Results: In the GS group were Pd value 36±16.7 msec, QTd 48.7±10.7 msec and heart rate (HR) 74±8 beat/min. In the control group were Pd 51±28 msec, QTd 53±12 msec and HR 78±10 beat/min. The Pd of patients group (p<0.001), QTd (p=0.038) and HR (p=0.021) were significantly lower than the control group. Conclusion: According to our study's results, in these patients, increased bilirubin levels are associated with decrease in HR, Pd and QTd, which consequently might decrease the incidence of cardiac arrhythmias and coronary artery disease. Further studies are needed to clarify the protective role of bilirubin in risk of arrhythmias in this category of patients. (

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“…In a population-based study involving 3285 adults and children by Macfarlane et al suggested that QT dispersion ≤50 ms indicated normality (15).…”

Section: Electrocardiographymentioning

confidence: 99%

Evaluation of the Frequency of QTc Dispersion and Its Relationship with Clinical and Laboratory Parameters in Dialysis Patients

Yilmaz¹,

Yildirim²,

Yilmaz³

et al. 2013

Turk Neph Dial Transpl

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OBJECTIVE:QTc dispersion is defi ned as the difference between the maximal and minimal correct QT interval on standard 12-lead ECG. Increased QTc dispersion has been reported in ESRD patients. In our study, we aimed to evaluate the frequency of QTc dispersion and its relationship between clinical and laboratory parameters in patients on regular dialysis programme. MATERIAL and METHODS:Sixty patients underwent dialysis (30 HD, 30 CAPD) and another 30 healthy subjects were enrolled into the study. The standard 12 lead ECGs were performed and QTcd was measured from all dialysis patients and control subjects. Blood samples were collected for the measurement of laboratory parameters. RESULTS:Dialysis patients showed signifi cantly higher QTcd than control subjects (55.75±36.48 versus 28.73±28.27; p=0.001). Patients with QTcd >50 ms had signifi cantly higher SBP, urea and ferritin levels, but signifi cantly lower iron binding capacity and calcium levels compared those with QTcd ≤ 50 ms(p<0.05). Positive correlations were found between QTcd and urea, ferritin and SBP levels, and inverse correlations with iron binding capacity level (p<0.05). CONCLUSION:The frequency of QTc dispersion was 40% among the dialysis patients .Although serum calcium was signifi cantly lower in patients who had QTcd >50 ms than QTcd ≤ 50 ms (p<0.05), there was no signifi cant correlation between QTcd and calcium. KEY WORDS:QTcd, Dialysis patients, Arrhythmia, Electrocardiography, Calcium ÖZ AMAÇ: 12 derivasyonlu standart EKG'de en uzun QTc mesafesi ile en kısa QTc mesafesi arasındaki fark QTc dispersiyonu olarak tanımlanır. SDBY hastalarında artmış QTc dispersiyonu bildirilmiştir. Biz çalışmamızda, diyaliz hastalarında QTc dispersiyonunun sıklığını ve klinik ve laboratuvar parametrelerle ilişkisinin değerlendirilmesini amaçladık. GEREÇ ve YÖNTEMLER:Çalışmaya 60 diyaliz hastası (30 HD, 30 PD) ve 30 sağlıklı birey dahil edildi. Tüm diyaliz hastalarının ve katılımcıların 12 derivasyonlu elektrokardiyografi leri çekildi ve QTcd ölçüldü. Laboratuvar parametreleri için kan örnekleri toplandı.BULGULAR: Diyaliz hastaları kontrol grubundan daha yüksek QTcd'ye sahipti (55,75±36,48 ve 28,73±28,27; p=0.001). QTcd >50 ms olan hastalar QTcd ≤ 50 ms olanlarla karşılaştırıldığında, SKB, üre ve ferritin anlamlı olarak daha yüksek, Ca ve demir bağlama kapasitesi anlamlı olarak daha düşüktü (p<0,05). QTcd ile üre, ferritin, SKB arasında pozitif, demir bağlama kapasitesi arasında ters korelasyon saptandı (p<0,05). SONUÇ:Diyaliz hastaları arasında QTc dispersiyonunun sıklığı %40'tı. QTcd >50 ms olan hastalarda, QTcd ≤ 50 ms olanlardan göre daha düşük serum kalsiyumu olmasına karşın, QTcd ve Ca arasında anlamlı bir korelasyon mevcut değildi.

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Influence of Lead Selection and Population on Automated Measurement of QT Dispersion

Cited by 131 publications

References 43 publications

Cardiac repolarization analysis using the surface electrocardiogram

Cardiac repolarization analysis using the surface electrocardiogram

The effect of Gilbert’s syndrome on the dispersions of QT and P-wave dispersion: an observational study

Evaluation of the Frequency of QTc Dispersion and Its Relationship with Clinical and Laboratory Parameters in Dialysis Patients

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