Harry L. Smith

Complete heart-block in hyperthyroidism following acute infections: A report of six cases with necropsy findings in one case

Abstract Six cases of exophthalmic goiter in which complete auriculoventricular dissociation occurred were observed at The Mayo Clinic. Three of the patients had had acute tonsillitis shortly preceding the onset of the arrhythmia and one patient had had scarlet fever. In the one fatal case, necropsy revealed an inflammatory lesion involving the region of the bundle of His, in which we were able to demonstrate gram-positive bacteria which we believed to be either diplococci or streptococci in short chains. In the two cases of the series in which development of the heart-block was not associated with acute infection, there is reason to believe that the heart-block was precipitated by the effect of digitalis on a previously injured auriculoventricular bundle. In those cases in which acute infection was present, evidence is advanced to indicate that the hyperthyroidism predisposed the patient to the development of acute infection, and also to secondary myocardial involvement which resulted in the occurrence of heart-block.