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.
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