Long QT Syndrome Associated with Adrenal Insufficiency in a Patient with Isolated Adrenocorticotropic Hormone Deficiency

QT prolongation and Torsades de Pointes were observed in a 44-year-old woman who had adrenal insufficiency caused by isolated adrenocorticotropic hormone deficiency. Although she had several risk factors for QT prolongation, we concluded that the adrenal insufficiency contributed to the QT prolongation, because the electrocardiographic changes were improved after steroid replacement therapy. It is known that the QT interval in a patient with adrenal insufficiency tends to be extended. However, reports on adrenal insufficiency in which the QT interval was sufficiently prolonged to cause Torsades de Pointes are rare. Clinicians should consider the possibility of adrenal insufficiency in patients with QT prolongation.