It has long been recognized that thyroid disease states exert profound effects on
the heart and cardiovascular system.
1
These include enhanced cardiac contractility, increased cardiac output, and decreased
systemic vascular resistance of hyperthyroidism, and impaired cardiac contractility,
decreased cardiac output, and increased systemic vascular resistance, which has been
uniformly observed with overt hypothyroidism.
2
Just as reproducible as the hemodynamic changes that accompany thyroid disease are
the reports that treatment with restoration of a euthyroid (normal T4, T3, thyroid stimulating hormone [TSH]) state leads to normalization of essentially every
cardiovascular parameter.
3
Although thyroid disease in all its forms affects approximately 12 million adults
in the American population, the prevalence of hypothyroidism is substantially greater
than that of thyrotoxicosis.
4
Advancing age produces an increase in the incidence of hypothyroidism, and after
age 60, disease prevalence may be as high as 12% to 15%.
5
Most patients, however, have relatively mild disease. This has been characterized
as “subclinical hypothyroidism,” based upon the fact that although the TSH is elevated
above the normal range (0.3 to 3.5 μIU/ml), it is <10 μIU/ml; serum total T4 and total T3 levels usually fall within the normal range. In these patients, the classic signs
and symptoms of hypothyrodism including fatigue, weight gain, constipation, and hypercholesterolemia;
hypertension and bradycardia are absent or only minimally abnormal. Thus, the decision
to initiate thyroid hormone replacement in this setting is controversial because studies
demonstrating the benefit of such treatment remain in conflict with other studies
showing no improvement.
6
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References
- Newly observed affectation of the thyroid gland in females.Lond Med Surg J. 1835; 7: 517-521
- Mechanisms of disease.N Engl J Med. 2001; 344: 501-509
- Enhanced left ventricular diastolic function in hyperthyroidism.J Clin Endocrinol Metab. 1991; 73: 146-150
Levey GS, Klein I. Disorders of the thyroid. In: Stein J, ed. Internal Medicine. 5th ed. Boston, MA: Little Brown & Co., 1998:1323–1349
- The Colorado thyroid prevalence study.Arch Int Med. 2000; 160: 526-534
- Effects of subclinical thyroid dysfunction on the heart.Ann Intern Med. 2002; 137: 904-914
- Biochemical basis of thyroid hormone action in the heart.Am J Med. 1990; 88: 626-630
- Effect of the thyroid state on myocardial contractility and ventricular ejection rate in man.Circulation. 1968; 34: 229-239
- Assessment of left ventricular diastolic function by radionuclide ventriculography at rest and exercise in subclinical hypothyroidism, and its response to l-thryoxine therapy.Am J Cardiol. 2003; 91: 1327-1330
- Effect of thyroid hormones on cardiac function, geometry, and oxidative metabolism assessed noninvasively by positron emission tomography and magnetic resonance imaging.J Clin Endocrinol Metab. 2000; 85: 1822-1827
- Subclinical hypothyroidism is an independent risk factor for atherosclerosis and myocardial infarction in elderly women.Ann Intern Med. 2000; 132: 270-278
- Low T3 syndrome.Circulation. 2003; 107: 708-713
- Thyroid hormone therapy of cardiovascular disease.Cardiovasc Rev Rep. 2002; 23: 20-26
Article info
Publication history
Accepted:
April 1,
2003
Received in revised form:
April 1,
2003
Received:
March 3,
2003
Identification
Copyright
© 2003 Excerpta Medica Inc. Published by Elsevier Inc. All rights reserved.
