Thyroid Hormone Improved Heart Function After Heart Attack

According to a study published by researchers in the Journal of Translational Medicine, the administration of thyroid hormone treatment improved heart function by reducing the loss of cardiac myocytes (heart muscle cells) at the time of myocardial infraction (heart attack).

Thyroid gland produces two significant hormones called T3 and T4. They play an important role in the regulation of heart rate. Slight increase in the thyroid hormone levels increases cardiac output and strengthens the cardiac muscles, whereas lower levels of the same may causes heart failure.

Earlier animal studies showed lower levels of T3 after the heart attack, which by itself can cause a heart failure. It was found by the scientists that blood hormone levels may not always reveal this cardiac tissue hormone deficiency.  In the recent study scientists treated rats after myocardial infraction with thyroid hormone and studied the changes at the cellular level.  After eight weeks of the treatment they noticed a significant reduction in the loss of myocytes which in turn improved the heart functioning. 

This study was funded by the National Institute of Health’s National Heart, Lung and Blood Institute and the American Heart Association. More research needs to be conducted on humans in the method of administering the hormone treatment and in determining which form of thyroid hormone (T3or T4) is more suitable. Overdosing the patients might cause arrhythmias. Experts believe that humans also might benefit similarly with the thyroid hormone treatment. They believe that recently developed new approach that restores cardiac tissue T3 while maintaining the normal serum hormone levels which worked well with rats might also work on humans. This new research could improve patient survival rates with cardiac diseases as thyroid hormone is easily available and inexpensive.