Chronic bifascicular block with intermittent complete atrioventricular block induced by hyperthyroidism

a Department of Internal Medicine, Department of Medicine, Taipei Medical University School of Medicine and Taipei Wan-Fang Hospital, Taiwan, R.O.C. b Division of Endocrinology and Metabolism, Department of Medicine, Taipei Medical University School of Medicine and Taipei Wan-Fang Hospital, Taiwan, R.O.C. c Division of Cardiovascular Medicine, Department of Medicine, Taipei Medical University School of Medicine and Taipei Wan-Fang Hospital, Taiwan, R.O.C. d Institute of Clinical Medicine, Yang-Ming University School of Medicine, Taiwan, R.O.C.