QT prolongation in a child with thyroid storm

Albert, Benjamin B.; Eckersley, Luke; Skinner, Jonathan R.; Jefferies, Craig

doi:10.1136/bcr-2013-202595

Cited by 9 publications

(3 citation statements)

References 16 publications

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“…Speculations of the reasons for these discrepancies between healthcare guidelines and day-to-day practice include, among others, the intra-subject variability of QTc intervals that does not allow monitoring QTc changes and/or detecting QTc abnormalities with sufficiently robust accuracy 14 . It is surely true that QTc interval changes may reflect not only treatment-related and channelopathy-based repolarisation abnormalities 2 but also electrolyte differences 15 , fever 16 , hormonal changes 17 , and alteration in autonomic and central nervous status 18 . Nevertheless, it is also apparent that imprecisions of QT interval measurement and inaccuracies of its heart rate correction may substantially contribute to an increased variability of measured QTc values 19 .…”

Section: Introductionmentioning

confidence: 99%

Influence of heart rate correction formulas on QTc interval stability

Andršová

Hnatkova²,

Šišáková

et al. 2021

Sci Rep

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Monitoring of QTc interval is mandated in different clinical conditions. Nevertheless, intra-subject variability of QTc intervals reduces the clinical utility of QTc monitoring strategies. Since this variability is partly related to QT heart rate correction, 10 different heart rate corrections (Bazett, Fridericia, Dmitrienko, Framingham, Schlamowitz, Hodges, Ashman, Rautaharju, Sarma, and Rabkin) were applied to 452,440 ECG measurements made in 539 healthy volunteers (259 females, mean age 33.3 ± 8.4 years). For each correction formula, the short term (5-min time-points) and long-term (day-time hours) variability of rate corrected QT values (QTc) was investigated together with the comparisons of the QTc values with individually corrected QTcI values obtained by subject-specific modelling of the QT/RR relationship and hysteresis. The results showed that (a) both in terms of short-term and long-term QTc variability, Bazett correction led to QTc values that were more variable than the results of other corrections (p < 0.00001 for all), (b) the QTc variability by Fridericia and Framingham corrections were not systematically different from each other but were lower than the results of other corrections (p-value between 0.033 and < 0.00001), and (c) on average, Bazett QTc values departed from QTcI intervals more than the QTc values of other corrections. The study concludes that (a) previous suggestions that Bazett correction should no longer be used in clinical practice are fully justified, (b) replacing Bazett correction with Fridericia and/or Framingham corrections would improve clinical QTc monitoring, (c) heart rate stability is needed for valid QTc assessment, and (d) development of further QTc corrections for day-to-day use is not warranted.

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Section: Introductionmentioning

confidence: 99%

Influence of heart rate correction formulas on QTc interval stability

Andršová

Hnatkova²,

Šišáková

et al. 2021

Sci Rep

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“…Hyperthyroidism is associated with QTc prolongation. There are case reports in the literature reporting QTc prolongation in hyperthyroidism, although there is not enough study on this subject [ 27 , 28 ]. In our study, there was no statistically significant difference between the QTc intervals in patients with and without HT.…”

Section: Discussionmentioning

confidence: 99%

Relationship between a Prolonged Corrected QT Interval and Mortality in Patients Presenting with Syncope at the Emergency Department

Akyol

Acar

Çakır

et al. 2021

BioMed Research International

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Background. Syncope is a common symptom in emergency department patients. Among various etiological factors, cardiac causes have the highest risk of mortality. The corrected QT interval is considered an independent predictor of mortality for many diseases. Objectives. Analyze QT interval analysis of patients presenting to the emergency department with syncope. Methods. In this prospective observational study, patients who presented to the emergency department with syncope between January 1, 2018, and January 1, 2019 were included. Results. The median age was 64 (49-78) years, and 58.8% of patients were male. The corrected QT interval (QTc) in patients with coronary artery disease and chronic obstructive pulmonary disease was longer than those without. There was no statistically significant association between hypertension, diabetes, stroke, thyroid disease, and prolonged QTc. Patients who did not survive had significantly prolonged QT intervals. According to ROC analysis, sensitivity of >440.5 ms QTc values in predicting mortality was 86% and specificity was 71% ( AUC = 0.815 ; 95 % CI = 0.71 − 0.91 ; p < 0.001 ). Conclusions. Patients admitted to emergency department with syncope and a prolonged QTc are associated with a higher mortality rate and thus can provide us with an important guide for the management of these patients.

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“…As well known, the duration of the QTc interval is influenced by plasma electrolytes (Facchini et al, 2006;Genovesi et al, 2008Genovesi et al, , 2019) that might easily change during the treatment course. QTc is also influenced by fever (Drew, Baranchuk, Hopman, & Brison, 2017) and many other conditions including central nervous (Capparelli et al, 2013) and hormonal changes (Albert, Eckersley, Skinner, & Jefferies, 2014). All this leads to variability in the sequentially measured QTc values that is not only challenging to control for but also makes it difficult to differentiate between the truly proarrhythmic signs and other influences of the repolarization control.…”

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confidence: 99%

Sources of QTc variability: Implications for effective ECG monitoring in clinical practice

Hnatkova

Malik

2019

Noninvasive Electrocardiol

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Pharmaceuticals that prolong ventricular repolarization may be proarrhythmic in susceptible patients. While this fact is well recognized, schemes for sequential QTc interval monitoring in patients receiving QT‐prolonging drugs are frequently overlooked or, if implemented, underutilized in clinical practice. There are several reasons for this gap in day‐to‐day clinical practice. One of these is the perception that serially measured QTc intervals are subject to substantial variability that hampers the distinction between potential proarrhythmic signs and other sources of QTc variability. This review shows that substantial part of the QTc variability can be avoided if more accurate methodology for electrocardiogram collection, measurement, and interpretation is used. Four aspects of such a methodology are discussed. First, advanced methods for QT interval measurement are proposed including suggestion of multilead measurements in problematic recordings such as those in atrial fibrillation patients. Second, serial comparisons of T‐wave morphologies are advocated instead of simple acceptance of historical QTc measurements. Third, the necessity of understanding the pitfalls of heart rate correction is stressed including the necessity of avoiding the Bazett correction in cases of using QTc values for clinical decisions. Finally, the frequently overlooked problem of QT‐heart rate hysteresis is discussed including the possibility of gross QTc errors when correcting the QT interval for simultaneously measured short‐term heart rate.

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QT prolongation in a child with thyroid storm

Cited by 9 publications

References 16 publications

Influence of heart rate correction formulas on QTc interval stability

Influence of heart rate correction formulas on QTc interval stability

Relationship between a Prolonged Corrected QT Interval and Mortality in Patients Presenting with Syncope at the Emergency Department

Sources of QTc variability: Implications for effective ECG monitoring in clinical practice

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