QT dispersion in hypothyroidism

Altun, Armağan; Altun, Gülay Durmuş; Özbay, Gültaç

doi:10.1016/s0167-5273(99)00178-3

Cited by 12 publications

(11 citation statements)

References 8 publications

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“…With regard to ventricular repolarization, our results showed a prolongation of the QT interval and an increased dispersion of the QT interval in hypothyroid patients, in agreement with previous observations (17,18). The increased regional inhomogeneity of Figure 2 In hypothyroid patients, SDNN (top) was inversely related (by simple regression) to serum (log)TSH levels (rZK0.48, P!0.006), while QTc dispersion (bottom) (rZ0.49, P!0.004) was directly related to (log)TSH.…”

Section: Discussionsupporting

confidence: 93%

Changes in heart rate variability and QT dispersion in patients with overt hypothyroidism

Galetta¹,

Franzoni²,

Fallahi³

et al. 2008

European Journal of Endocrinology

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Objective: The aim of the present study was to evaluate the effect of clinical hypothyroidism on cardiovascular autonomic function and ventricular repolarization. Design and methods: We studied 31 patients (22 females and 9 males; mean age 53.6G11.8 years) with overt hypothyroidism (TSHZ56.2G14.7 mU/ml, low free thyroxine (T 4 ), free tri-iodothyronine (T 3 )) and 31 euthyroid controls, to investigate the dispersion of the QT interval in electrocardiogram (ECG) (an index of inhomogeneity of repolarization) and heart rate variability (HRV; a measure of cardiac autonomic modulation). The hypothyroid patients and controls underwent a full medical examination, standard 12-lead ECG, and 24-h ambulatory ECG monitoring. The hypothyroid patients were re-examined after 6 months of treatment with L-T 4 . Results: Patients with hypothyroidism showed higher QT dispersion and lower HRV measures than controls (P!0.01 or P!0.001). In hypothyroid patients, standard deviation of all R-R intervals was inversely related (by simple regression) to serum (log)TSH levels (rZK0.47, PZ0.008), while QT dispersion (rZ0.50, PZ0.004) and QTc dispersion (rZ0.46, PZ0.008) were directly related to (log)TSH. Parameters of HRV improved after 6 months of L-T 4 treatment, with the correction of hypothyroidism, becoming comparable with those of the control subjects, whereas the QT and QTc dispersion results were found to be only partially restored, remaining higher than the controls. Conclusions:The results of the study demonstrate that hypothyroidism is associated with a decreased sympatho-vagal modulation of the heart rate and with an increased inhomogeneity of ventricular recovery times. The assessment of HRV and QT dispersion in patients with overt hypothyroidism may represent a useful tool in monitoring the cardiovascular risks.European Journal of Endocrinology 158 85-90

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Section: Discussionsupporting

confidence: 93%

Changes in heart rate variability and QT dispersion in patients with overt hypothyroidism

Galetta¹,

Franzoni²,

Fallahi³

et al. 2008

European Journal of Endocrinology

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“…Evident hypothyroidism is known to affect the heart electrophysiology . However, despite these findings in patients with evident hypothyroidism, there are very few studies which have evaluated the effects of SH on the heart electrophysiology.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of QT dispersion and Tp‐e interval in children with subclinical hypothyroidism

Akın

Ünal

Yıldırım

et al. 2018

Pacing Clinical Electrophis

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The current study is the first to have shown significantly increased QTd, QTcd, Tp-e, Tp-e/QT ratio, and Tp-e/QTc ratio in children diagnosed with SH. A positive correlation was determined between TSH and maximum QT values, Tp-e, Tp-e/QT ratio, and Tp-e/QTc ratio. These results suggest the need to further assess the long-term risks of prolonged QT dispersion in the setting of subclinical hypothyroidism.

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“…(figure 1). Conflicting results have been reported on the prognostic value of QTd in patients following acute myocardial infarction (12–16), and in other clinical settings (17–21) including acute stroke (22, 23). Therefore its association and predictive value in acute stroke remains controversial.…”

Section: Introductionmentioning

confidence: 99%

Relationship between QT Interval Dispersion in Acute Stroke and Stroke Prognosis: A Systematic Review

Lederman

Balucani

Lazar

et al. 2014

Journal of Stroke and Cerebrovascular Diseases

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Background QT dispersion (QTd) has been proposed as an indirect ECG measure of heterogeneity of ventricular repolarization. The predictive value of QTd in acute stroke remains controversial. We aimed to clarify the relationship between QTd and acute stroke and stroke prognosis. Methods A systematic review of the literature was performed using pre-specified medical subjects heading (MeSH) terms, Boolean logic and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Eligible studies (a) included ischemic or hemorrhagic stroke and (b) provided QTd measurements. Results Two independent reviewers identified 553 publications. Sixteen articles were included in the final analysis. There were a total of 888 stroke patients: 59% ischemic and 41% hemorrhagic. There was considerable heterogeneity in study design, stroke subtypes, ECG assessment-time, control groups and comparison groups. Nine studies reported a significant association between acute stroke and baseline QTd. Two studies reported that QTd increases are specifically related to hemorrhagic strokes, involvement of the insular cortex, right-side lesions, larger strokes, and increases in 3, 4-dihydroxyphenylethylene glycol in hemorrhagic stroke. Three studies reported QTd to be an independent predictor of stroke mortality. One study each reported increases in QTd in stroke patients who developed ventricular arrhythmias and cardiorespiratory compromise. Conclusions There are few well-designed studies and considerable variability in study design in addressing the significance of QTd in acute stroke. Available data suggest that stroke is likely to be associated with increased QTd. While some evidence suggests a possible prognostic role of QTd in stroke, larger and well-designed studies need to confirm these findings.

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QT dispersion in hypothyroidism

Cited by 12 publications

References 8 publications

Changes in heart rate variability and QT dispersion in patients with overt hypothyroidism

Changes in heart rate variability and QT dispersion in patients with overt hypothyroidism

Evaluation of QT dispersion and Tp‐e interval in children with subclinical hypothyroidism

Relationship between QT Interval Dispersion in Acute Stroke and Stroke Prognosis: A Systematic Review

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