Thyroid hormone is very important for normal cardiovascular function. When there is not enough thyroid hormone, neither the heart nor the blood vessels can function normally. In hypothyroidism, the reduced level of thyroid hormone causes the heart muscle to pump less vigorously, and eventually to become weakened. In addition, the heart muscle cannot fully relax after each heart beat.
Conversion is the act or process of changing something into a different state or form. ...the conversion of disused rail lines into cycle routes. A loft conversion can add considerably to the value of a house.
Energy conversion. The process of changing energy from one form to another. There are many conversion processes that appear as routine phenomena in nature, such as the evaporation of water by solar energy or the storage of solar energy in fossil fuels.