Thyrotoxicosis developed in a patient while receiving thyroid hormone therapy for clinical hypothyroidism. The development of second-degree heart block of Mobitz type 1 variety was followed by third- and then firstdegree heart block. We conclude that the varying degrees of heart block were secondary to hyperthyroxinemia caused by Graves' disease and exogenous thyroid hormone.
(JAMA 239:1644-1646, 1978)
Eraker SA, Wickamasekaran R, Goldman S. Complete Heart Block With Hyperthyroidism. JAMA. 1978;239(16):1644-1646. doi:10.1001/jama.1978.03280430060018