Cardiovascular manifestations are some of the most profound and characteristic symptoms and signs of hyperthyroidism. <sup>16 Klein I. Thyroid hormone and the cardiovascular system Am J Med 1990 ;  88 : 631  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 37 Polikar R., Burger A.G., Scherrer U. , e al. The thyroid and the heart Circulation 1993 ;  87 : 1435

Cliccare qui per andare alla sezione Riferimenti</sup> Since the first descriptions 200 years ago by Perry and Graves, clinicians have noted the finding of a hyperdynamic cardiovascular system resulting from excess thyroid hormone secretion by the thyroid gland. More recently, similar changes have been linked to treatment with l-thyroxine in dosages which suppress thyroid-stimulating hormone. <sup>2 Biondi B., Fazio S., Carella C. , e al. Cardiac effects of long-term thyrotropin-suppressive therapy with levothyroxine J Clin Endocrinol Metab 1993 ;  77 : 334  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Understanding the mechanisms by which thyroid hormone affects the cardiovascular system provides a basis for the management of patients with thyrotoxic heart disease. This review examines these molecular mechanisms in naturally occurring thyroid disease states and the potential utility of thyroid hormone therapy in the management of patients with various forms of cardiovascular disease. <sup>20 Klein I., Ojamaa K. Cardiovascular manifestations of endocrine disease J Clin Endo Metab 1992 ;  75 : 339  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 22 Klemperer J.D., Ojamaa K., Klein I. Thyroid hormone therapy in cardiovascular disease Prog Cardiovasc Dis 1996 ;  38 : 329  [cross-ref]

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The changes in cardiovascular hemodynamics that accompany thyrotoxicosis are summarized in Table 1. There are striking similarities between the clinical presentation of the hyperadrenergic state that accompanies pheochromocytoma and the cardiovascular hemodynamics of hyperthyroidism. <sup>25 Levey G.S., Klein I. Catecholamine-thyroid hormone interactions and the cardiovascular manifestations of hyperthyroidism Am J Med 1990 ;  88 : 642  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 45 Ventrella S., Klein I. Beta-adrenergic receptor blocking drugs in the management of hyperthyroidism The Endocrinologist 1994 ;  4 : 391  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> This has led to the suggestion that thyrotoxicosis is associated with excessive catecholamine secretion. <sup>37 Polikar R., Burger A.G., Scherrer U. , e al. The thyroid and the heart Circulation 1993 ;  87 : 1435

Cliccare qui per andare alla sezione Riferimenti</sup> Historically, observations relating to the clinical manifestations of hyperthyroidism emphasize the importance of heightened cardiovascular responses to exogenously administered catecholamines. These findings served as a basis for establishing one of the earliest diagnostic tests for hyperthyroidism. In 1918 Goetsch <sup>12 Goetsch E. Adrenaline hypersensitivity in clinical states of hyperthyroidism NY State J Med 1918 ;  18 : 259

Cliccare qui per andare alla sezione Riferimenti</sup> reported marked cardioacceleration and blood pressure responses to injections of epinephrine in the hyperthyroid patient. The magnitude of these responses was observed to be less in euthyroid individuals.

Hyperthyroidism potentiates not only cardiovascular symptoms but other responses such as diaphoresis, tremor, and hepatic glycogenolysis normally associated with excessive catecholamine stimulation. <sup>19 Klein I., Trzepacz P., Roberts M. , e al. Symptom rating scale for assessing hyperthyroidism Arch Intern Med 1988 ;  148 : 387  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 27 Liggett S.B., Shah S.D., Cryer P.E. Increased fat cell and skeletal muscle beta-adrenergic receptor densities but unattended lipolytic, glycemic and cardiac chronotropic in vivo in experimental human thyrotoxicosis J Clin Invest 1989 ;  83 : 803  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 45 Ventrella S., Klein I. Beta-adrenergic receptor blocking drugs in the management of hyperthyroidism The Endocrinologist 1994 ;  4 : 391  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> These findings led to the conclusion that hyperthyroidism was a bihormonal disease state involving both excessive thyroid hormone and catecholaminergic action. Although prior reports have proposed altered catecholamine sensitivity of the heart and other organs in hyperthyroidism, critical review of these studies does not support the pharmacologic concept of the enhanced biologic responsiveness. <sup>25 Levey G.S., Klein I. Catecholamine-thyroid hormone interactions and the cardiovascular manifestations of hyperthyroidism Am J Med 1990 ;  88 : 642  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> When various measures such as heart rate or cardiac contractile response to exogenously administered catecholamines have been studied, no convincing evidence of a lower threshold or a shift in the dose-response relationship has been observed. <sup>27 Liggett S.B., Shah S.D., Cryer P.E. Increased fat cell and skeletal muscle beta-adrenergic receptor densities but unattended lipolytic, glycemic and cardiac chronotropic in vivo in experimental human thyrotoxicosis J Clin Invest 1989 ;  83 : 803  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Studies in experimental animals and subhuman primates have confirmed that the metabolic and hemodynamic sensitivity to exogenous catecholamines is unaltered in experimental hyperthyroidism. <sup>14 Hoit B.D., Khoury S.F., Shao Y. Effects of thyroid hormone on cardiac beta-adrenergic responsiveness in conscious baboons Circulation 1997 ;  96 : 592

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