Bonelli N, et al. - Researchers carried out this study to investigate the effect of an iodine load on thyroid function of patients with ischemic heart disease (IHD) and the long-term influence of unknown subclinical hyperthyroidism. In IHD, the prevalence of spontaneous subclinical hyperthyroidism was surprisingly elevated. It was further increased by iodine load, especially in patients with thyroid nodules and familial history of thyroid diseases, persisting in a not negligible number of them even after one year.