T3, Hypothyroidism, and Heart Disease: Medical Journals

Purpose of this compilation

To show that low levels of the thyroid hormone T3 (triiodothyronine) may correlate with heart disease. This finding is in contrast to the belief that patients with hypothyroidism and heart disease should not be treated with T3 in addition to T4 (thyroxine). While caution is still necessary, not treating a hypothyroid patient with T3 may present its own risks.

1. "Low-T3 syndrome: a strong prognostic predictor of death in patients with heart disease" (Italy, 2003)

Clinical and experimental data have suggested a potential negative impact of low-T3 state on the prognosis of cardiac diseases. The aim of the present prospective study was to assess the role of thyroid hormones in the prognosis of patient population with heart disease....Conclusions: Low-T3 syndrome is a strong predictor of death in cardiac patients and might be directly implicated in the poor prognosis of cardiac patients.

Iervasi G, Pingitore A, Landi P, et al. Low-T3 syndrome: a strong prognostic predictor of death in patients with heart disease. Circulation 2003 Feb 11;107(5):708-13.

Abstract online at <www.circ.ahajournals.org/cgi/content/abstract/107/5/708>.

2. "[Serum thyroid hormone levels correlate with cardiac function and ventricular tachyarrhythmia in patients with chronic heart failure]" [Article in Japanese; abstract in English] (Japan, 1993)

Decreased FT3 levels and FT3/FT4 ratios, and increased rT3 levels were associated with worse NYHA [New York Heart Association] class. FT3/FT4 was positively and rT3 was negatively correlated with echocardiographical fractional shortening. FT3 and rT3 were negatively and positively correlated with mean daily heart rates, in contrast to known hypothyroid patients. Patients with ventricular tachycardia demonstrated significantly lower serum values of FT3 and FT3/FT4, and significantly higher values of rT3.

Shimoyama N, Maeda T, Inoue T, Niwa H, Saikawa T. [Serum thyroid hormone levels correlate with cardiac function and ventricular tachyarrhythmia in patients with chronic heart failure]. J Cardiol 1993;23(2):205-13.

Abstract online at <www.ncbi.nlm.nih.gov>.