Thyrotoxicosis is conspicuous because of its influence on the rate of the heart, and many of its most interesting symptoms originate in that organ. As early as 1786 Parry realized the connection between cardiac symptomatology and goiter, but to his mind the heart disease was the primary condition. He thought also that exophthalmos, which was present in his eight patients, was secondary to the heart disease. Even Graves, Stokes, and others in the mid 19th century were of the same opinion, and it was not until 1883 and 1885 that Kocher, and, independently, Horsley, recognized the part played in this syndrome by the thyroid hormone. In 1899 Kraus published in Wiener klinische Wochenschrift his concept of the so-called neurotic or thyrotoxic heart from which the current ideas have been developed.
At first, interest was centered entirely on the heart in hyperthyroidism. Did toxic diffuse (exophthalmic) goiter produce hypertrophy of the