Hypothyroidism is a condition in which the thyroid gland doesn't produce enough thyroid hormone.
Hypothyroidism's deficiency of thyroid hormones can disrupt such things as heart rate, body temperature, and all aspects of metabolism.
Low levels of thyroid-producing hormones, such as triiodothyronine (T3) and thyroxine (T4), can change the way the body processes fat. This can cause high cholesterol and atherosclerosis, which can potentially lead to serious heart-related problems, such as angina and a heart attack.