Thyroid Research Thyroid Research Archive Nonthyroidal Illness

3,5-Diiodothyropropionic acid improves cardiac function in patients with heart failure

(November 2002)

The background of the study. Patients with heart failure may have low serum triiodothyronine (T3) concentrations, which may aggravate their heart failure by decreasing cardiac contractility and increasing resistance to blood flow. This study evaluated the effects of 3,5-diiodothyropropionic acid (DITPA, a thyroid hormone analog that increases cardiac function in animals, in normal subjects, and in patients with congestive heart failure.

How the study was done. The study subjects were seven normal men and 21 patients with congestive heart failure. The normal subjects were given 1.875 mg/kg of DITPA daily for two weeks and then 3.75 mg/kg daily for two weeks. The patients with heart failure received 1.875 mg/kg of DITPA daily for two weeks and then 3.75 mg/kg daily for two weeks, or placebo. Body weight, heart rate, blood pressure, cardiac function, and serum thyrotropin (TSH) were measured before and at the end of each treatment period. The patients underwent cardiac catheterization, echocardiography, and measurements of ejection fraction by radionuclide imaging at base line and at four weeks.

The results of the study. There were no changes in weight, heart rate, or blood pressure after administration of DITPA for two and four weeks in the normal men. Their mean serum TSH concentration fell from 3.5 to 0.4 mU/L at four weeks, evidence that DITPA has some thyroid hormone actions.

Nineteen patients with heart failure completed the study, 9 in the DITPA-treatment group and 10 in the placebo group. There were no changes in weight, heart rate, or blood pressure during treatment in either group. The mean serum TSH concentration decreased from 2.5 to 0.02 mU/L in the DITPA-treatment group, but there was no change in the placebo group. There were no changes in cardiac function in the placebo group, but there was a statistically significant increase in cardiac index and a decrease in vascular resistance in the DITPA treatment group.

The conclusions of the study. In patients with heart failure the thyroid hormone analog DITPA increases cardiac output and decreases vascular resistance.

The original article. Morkin E, Pennock G, Spooner PH, Bahl JJ, Underhill Fox K, Goldman S. Pilot studies on the use of 3,5-diiodothyropropionic acid, a thyroid hormone analog, in the treatment of congestive heart failure. Cardiology 2002;97:218-25.