title: Unusual Manifestation of Graves' Disease: Ventricular Fibrillation.
abstract: BACKGROUND
  It is well known that thyrotoxicosis causes rhythm disorders including sinus tachycardia, atrial fibrillation, and atrial flutter. Atrial fibrillation is the most common arrhythmia in thyrotoxicosis, occurring in 5-15% of patients over 60 years of age, whereas ventricular arrhythmia is an unusual manifestation.
  
  
  METHODS
  An 18-year-old Japanese woman was admitted to our emergency department because of loss of consciousness caused by ventricular fibrillation. She had been diagnosed with Graves' disease only 5 days earlier and had no other past medical history. Blood examination showed no obvious abnormality except thyrotoxicosis, 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.
  
  
  CONCLUSIONS
  This case highlights that thyrotoxicosis can, albeit extremely rarely, cause ventricular fibrillation even in the absence of hypokalemia or underlying cardiovascular disease.
authors.affiliation: Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kobayashi
authors.affiliation: Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Haketa
authors.affiliation: Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Abe
authors.affiliation: Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Tahira
authors.affiliation: Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Hatanaka
authors.affiliation: Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ueno
authors.affiliation: Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Soma
keywords: Coronary artery vasospasm; Early repolarization syndrome; Graves’ disease; Thyrotoxicosis; Ventricular fibrillation