Subclinical Hypothyroidism and Euthyroid Sick Syndrome in Patients with Moderate-to-Severe Congestive Heart Failure.

Thyroid function tests were performed on baseline plasma that had been taken from 34 patients with NYHA Class II or Class III congestive heart failure (CHF). All patients were negative for thyroid disease on history and physical examination and none was taking medication known to alter thyroid metabolism. Analysis of thyroid function revealed abnormalities in 16 of 31 patients.