Unusual Manifestation of Graves' Disease: Ventricular Fibrillation

Abstract

toxicosis, and coronary angiography revealed patent coronary arteries. She was diagnosed with thyroid storm due to Graves' disease and is currently healthy during outpatient follow-up. Conclusion: This case highlights that thyrotoxicosis can, albeit extremely rarely, cause ventricular fibrillation even in the absence of hypokalemia or underlying cardiovascular disease.

Cardiac Arrhythmias in Autoimmune Diseases

“…75 There is also a single report of ventricular arrhythmias among GD patients. 76 AF in hyperthyroid patients is explained by a decreased atrial refractory period, increased sympathetic tone with decreased HRV, and automaticity in the pulmonary vein. 77 Watanabe et al found that decreased the atrial refractory period is caused by thyroid hormone-mediated decreases in the expression of L-type calcium channel mRNA and increased expression of the Kv1.5 potassium channel.…”

Ventricular fibrillation in Graves disease reveals a rare SCN5A mutation with W1191X variant associated with Brugada syndrome

“…Ventricular arrhythmias rarely occur in hyperthyroidism. [1][2][3] Although atrial fibrillation is the most common arrhythmia seen in 5-15% of patients with hyperthyroidism, the varied regional distribution of β-1 and -2 adrenergic receptors between the atria and ventricles may account for Beta blocker overdose was also questioned as a possible cause of her cardiac arrest. Although propranolol typically leads to bradyarrhythmias, it has a higher membrane stabilizing activity compared to other beta blockers which can inhibit myocardial fast sodium channels and result in wide QRS dysrhythmias.…”

“…Ventricular arrhythmias rarely occur in hyperthyroidism. 1 , 2 , 3 Although atrial fibrillation is the most common arrhythmia seen in 5%–15% of patients with hyperthyroidism, the varied regional distribution of β-1 and β-2 adrenergic receptors between the atria and ventricles may account for individual predisposition to either ventricular or atrial arrhythmias. 2 Thyroid hormones exert different effects on cardiac myocytes in both a genomic and nongenomic manner.…”

Ventricular fibrillation associated with Graves' disease and amiodarone induced thyrotoxicosis

“…As discussed earlier, although very rare, new onset thyrotoxicosis can precipitate VF theoretically by inducing coronary vasospasm leading to myocardial ischemia. Another proposed mechanism is that thyrotoxicosis is associated with early repolarization that can exaggerate the J-point elevation and induce VF [2]. Advanced heart failure marked by maladaptive hypertrophic and fibrotic myocardial remodeling, with or without dyssynchronous contraction, can predispose the heart to the whole spectrum of ventricular arrhythmias [3].…”

“…Thyroid dysfunction produce changes in cardiac contractility, myocardial oxygen consumption, cardiac output, blood pressure, and systemic vascular resistance (SVR) [1]. Although it is well known that thyrotoxicosis can cause sinus tachycardia, atrial fibrillation (Afib) and atrial flutter, ventricular fibrillation (VF) is extremely rare [2]. In thyrotoxicosis, cardiac contractility is enhanced, resting heart rate is increased, and SVR is decreased leading to an increase in cardiac output by 50-300%.…”