Heart Failure Caused by Atrial Fibrillation in a Patient with Isolated Adrenocorticotropic Hormone Deficiency and Hashimoto's Thyroiditis.

We report the case of a 75-year-old female patient with a history of Hashimoto's thyroiditis who presented with congestive heart failure caused by atrial fibrillation associated with isolated adrenocorticotropic hormone (ACTH) deficiency. This is the first case of the combination of these complex conditions. Clinical conditions in a patient with isolated ACTH deficiency and Hashimoto's thyroiditis can be variable. Thus, it is sometimes difficult to establish a diagnosis. The mechanism underlying heart failure may be complex in some cases. Various conditions can affect patients simultaneously. Therefore, making a proper diagnosis is necessary to improve the patient's prognosis.