The cardiovascular manifestations of thyrotoxicosis such as tachycardia, palpitations, and increased pulse pressure are well known. In some instances of thyrotoxicosis chest roentgenograms show straightening of the left cardiac border which simulates the roentgenographic pattern seen in patients with auricular enlargement.1 Likewise, in patients with hyperthyroidism a variety of electrocardiographic changes have been described. These include sinus tachycardia, auricular fibrillation, increased amplitude of R-II, and increased duration of the QRS complex.1 However, the more recent reports of the electrocardiographic changes in thyrotoxicosis, while stressing the above changes, do not report any alterations in the P-R interval.2
Our interest in changes in the P-R interval in the electrocardiograms of patients with thyrotoxicosis was stimulated by the question of whether a patient with thyrotoxicosis, straightening of the left cardiac border on chest roentgenogram, sinus tachycardia at a rate of 126 and a P-R interval of 0.26 seconds had intrinsic
Blizzard JJ, Rupp JJ. PROLONGATION OF THE P-R INTERVAL AS A MANIFESTATION OF THYROTOXICOSIS. JAMA. 1960;173(16):1845. doi:10.1001/jama.1960.73020340015019c
Customize your JAMA Network experience by selecting one or more topics from the list below.
Create a personal account or sign in to: