QT Prolongation due to Graves’ Disease

Kulairi, Zain; Deol, Nisha; Tolly, Renee; Manocha, Rohan; Naseer, Maliha

doi:10.1155/2017/7612748

Cited by 5 publications

(12 citation statements)

References 6 publications

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“…Numerous studies have shown a strong association between hyperthyroidism and QTc prolongation. A positive correlation between free T4 and the degree of QT prolongation was seen; patients with higher levels of free T4 had longer QTc duration [1,[3][4][5][6][7][8]. This positive correlation was present with our patient: as free T4 increased, QTc also increased ( Table 1).…”

Section: Discussionsupporting

confidence: 69%

“…This positive correlation was present with our patient: as free T4 increased, QTc also increased (Table 1 ). Normalization of free T4 leads and achievement of the euthyroid state has been shown to normalize QTc duration in hyperthyroid patients [ 4 ]. Although repeat-free T4 was not done in our patient after high dose methimazole treatment, serial QTc did show significant and continued improvement (Figure 1 and Table 1 ).…”

Section: Discussionmentioning

confidence: 99%

“…Factors that contribute to a fatal arrhythmia are thyrotoxicosis in the setting of an already weakened heart, seen in our patient. Literature review shows that ventricle repolarization is greatly affected in hyperthyroidism [3][4][5]. Ventricular repolarization is assessed using the QT interval corrected for the heart rate (QTc) on an electrocardiogram (ECG).…”

Section: Introductionmentioning

confidence: 99%

“…Research shows a significant positive correlation between QTc and thyroid hormones, especially free T4 levels. However, the mechanism and pathophysiology are not well understood [4][5][6][7][8]. The correlation has even been reported in patients with subclinical hyperthyroidism [7].…”

Section: Introductionmentioning

confidence: 99%

“…The most common cardiac complication is atrial fibrillation which occurs in approximately 15% of overtly hyperthyroid patients [ 3 ]. The occurrence of dangerous arrhythmias such as ventricular fibrillation (VF), although rare, can cause sudden cardiac death [ 4 ]. Malignant ventricular arrhythmias secondary to QT prolongation from thyrotoxicosis are seldom encountered in the inpatient setting.…”

Section: Introductionmentioning

confidence: 99%

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Ventricular Fibrillation: Potential Deadly Consequence of Discontinuation of Methimazole Prior to Radioiodine Ablation

Sikandar¹,

Mmagu²

2021

Cureus

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The following case involves a 62-year-old female patient suffering from heart failure with reduced ejection fraction (HFrEF) secondary to non-ischemic cardiomyopathy and Graves disease, who developed ventricular fibrillation (VF) after discontinuation of methimazole in preparation for radioiodine ablation. Electrocardiogram (ECG) showed a severely prolonged QTc in the setting of thyrotoxicosis, which significantly improved with high dose methimazole. VF secondary to thyrotoxicosis has rarely been reported and the literature review shows scarce data on its mechanism. Our case demonstrates not only a possible mechanism for the arrhythmia, but also highlights a potential risk factor for it. The report details how discontinuing antithyroid medication leads to VF in our patient and reviews the current literature on antithyroid withdrawal prior to radioiodine ablation therapy. Caution should be taken when discontinuing antithyroid medications in patients with advanced heart failure as potentially lethal ventricular arrhythmias can ensue.

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Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Ventricular Fibrillation: Potential Deadly Consequence of Discontinuation of Methimazole Prior to Radioiodine Ablation

Sikandar¹,

Mmagu²

2021

Cureus

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European Heart Rhythm Association (EHRA) position paper on arrhythmia management and device therapies in endocrine disorders, endorsed by Asia Pacific Heart Rhythm Society (APHRS) and Latin American Heart Rhythm Society (LAHRS)

et al. 2018

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Endocrine disorders are associated with various tachyarrhythmias, including atrial fibrillation (AF), ventricular tachycardia (VT), ventricular fibrillation (VF), and bradyarrhythmias. Along with underlying arrhythmia substrate, electrolyte disturbances, glucose, and hormone levels, accompanying endocrine disorders contribute to development of arrhythmia. Arrhythmias may be life-threatening, facilitate cardiogenic shock development and increase mortality. The knowledge on the incidence of tachy- and bradyarrhythmias, clinical and prognostic significance as well as their management is limited; it is represented in observational studies and mostly in case reports on management of challenging cases. It should be also emphasized, that the topic is not covered in detail in current guidelines. Therefore, cardiologists and multidisciplinary teams participating in care of such patients do need the evidence-based, or in case of limited evidence expert-opinion based recommendations, how to treat arrhythmias using contemporary approaches, prevent their complications and recurrence in patients with endocrine disorders. In recognizing this close relationship between endocrine disorders and arrhythmias, the European Heart Rhythm Association (EHRA) convened a Task Force, with representation from Asia-Pacific Heart Rhythm Society (APHRS) and Sociedad Latinoamericana de Estimulación Cardíaca y Electrofisiología (SOLAECE), with the remit of comprehensively reviewing the available evidence and publishing a joint consensus document on endocrine disorders and cardiac arrhythmias, and providing up-to-date consensus recommendations for use in clinical practice.

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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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QT Prolongation due to Graves’ Disease

Cited by 5 publications

References 6 publications

Ventricular Fibrillation: Potential Deadly Consequence of Discontinuation of Methimazole Prior to Radioiodine Ablation

Ventricular Fibrillation: Potential Deadly Consequence of Discontinuation of Methimazole Prior to Radioiodine Ablation

European Heart Rhythm Association (EHRA) position paper on arrhythmia management and device therapies in endocrine disorders, endorsed by Asia Pacific Heart Rhythm Society (APHRS) and Latin American Heart Rhythm Society (LAHRS)

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

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