Abstract
Myxedema coma occurs mostly in patients with longstanding untreated or undertreated hypothyroidism. Bradycardia is a well-known cardiac manifestation for myxedema coma; however, not all bradycardia with hypothyroidism are sinus bradycardia. Sick sinus syndrome is a group of arrhythmias caused by the malfunction of the natural pacemaker of the heart. Tachy-Brady syndrome is considered to be a type of sick sinus syndrome, where the heart alternates between tachycardia and bradycardia, and it is usually treated with pacemaker implantation along with rate slowing medical therapy. Here we report a case of an 83-year-old female who presented with myxedema coma and atrial fibrillation with tachycardia and intermittent slow ventricular response. We attempt to review the relationship between these two diseases and conclude that appropriate diagnosis of myxedema coma, may be beneficial in reducing the need for pacemaker implantation.