36 This review highlights a growing body of evidence from animal studies and small-scale clinical trials suggesting that low cellular thyroid activity at the cardiac tissue level may adversely affect HF progression and that treatment may lead to improvement.
Correspondence to A. Martin Gerdes, PhD, Cardiovascular Health Research Center, 1100 E 21st St, Suite 700, Sioux Falls, SD 57105. E-mail mgerdesatusd. edu Key Words: Heart failure (HF) is a major public health and economic problem in Western countries and is one of the most common causes of hospitalization and death.
This is increased at intervals of 3-4 weeks until the predicted dose is reached. Patients should feel some symptomatic improvement within two weeks of starting thyroxine. It may take 3-4 months for the full benefit of the drug to become apparent and for the TSH to normalise.
Regional expression of the type 3 iodothyronine deiodinase messenger ribonucleic acid in the rat central nervous system and its regulation by thyroid hormone. Endocrinology. 1999;140:784790. Schweizer U, Weitzel JM, Schomburg L.
Maintenance of TH homeostasis is required for proper cardiovascular function. Bioactive T3 is a powerful regulator of inotropic and lusitropic properties of the heart through their effects on myosin isoforms and calcium handling proteins in particular.
In addition, hypothyroid hearts show poor substrate use such as glucose, la.
Standards of Care Committee, American Thyroid Association. JAMA. 1995;273:808812. Roos A, Linn-Rasker SP, van Domburg RT, et al. The starting dose of levothyroxine in primary hypothyroidism treatment: A prospective, randomized, double-blind trial.
7 I advise women taking thyroxine who are planning to conceive to increase their dose of thyroxine by 30 at the confirmation of the pregnancy. TSH should be monitored every 8-10 weeks during pregna.
28 In addition, in chronic HF patients, TSH levels even slightly above normal range are independently associated with a greater likelihood of HF progression. 29 Epidemiological data also suggest that scHypo may be the only reversible cause of left ventricular (LV) diastolic dysfunction with slowed myocardial relaxation and impaired filling, particularly in subjects with TSH.
Treatment Primary hypothyroidism is treated by giving the patient replacement thyroxine, usually for life. Liothyronine rarely needs to be used unless there is life-threatening hypothyroidism. Alternative sources of thyroid hormones such as thyroid extracts should be avoided.
Thyroxine can be used to control symptoms if required while recovery occurs. Lithium- and amiodarone-induced hypothyroidism are managed with thyroxine. The ongoing need for the lithium or amiodarone should be considered, but they can be continued if necessary.
Monitoring and dose adjustment In primary hypothyroidism the TSH alone can be used to monitor therapy. The aim should be to maintain the TSH at the lower end of the normal range ( mIU/L).