title: Cyclic sinus node dysfunction in a patient with hyperthyroidism.
abstract: In a 54-year-old woman with hyperthyroidism, episodic sinus node dysfunction (SND) recurred in a cyclic fashion. The SND occurred suddenly during normal sinus rhythm and progressed to marked sinus bradycardia; occasionally, sinus arrest developed with or without ventricular escape beats. A 1-mg dose of intravenous atropine sulfate suppressed the occurrence transiently. After a 200-mg dose of propylthiouracil and a 20-mg dose of prednisolone every six hours, the SND was completely abolished within 21 hours. It is probable that, together with a pathologic process induced by hyperthyroidism, the autonomic nervous system participated in our patient's episodic SND.
mesh_terms: D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D001919:Bradycardia / Q000503:physiopathology; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000503:physiopathology*; D008875:Middle Aged; D012849:Sinoatrial Node / Q000503:physiopathology*