Hashimoto's thyroiditis and congenital long QT syndrome: a dangerous addition causing torsades—case report

Hypothyroidism is linked to electrocardiographic abnormalities such as sinus bradycardia, QT interval prolongation, malignant ventricular arrhythmias such as ventricular premature beat, ventricular tachycardia, TdP, and ventricular fibrillation. Assessment of thyroid function is of high value in QT prolongation syndromes to avoid SCD incidence. Thyroid hormone influences ventricular inhomogeneity, and L-thyroxine replacement treatment may minimize malignant ventricular arrhythmia and sudden cardiac death in patients with primary hypothyroidism. Our case highlights the importance of urgent electrolyte replacement and levothyroxine therapy to avoid the risk of ventricular arrhythmias.