Hypothyroidism occurs when the thyroid produces less thyroid hormone than the body needs.
Symptoms include fatigue, muscle pain, brittle nails and hair, depression, facial swelling, joint pain, weight gain and an increased sensitivity to cold temperatures. Doctors treat an underactive thyroid by giving patients medications designed to restore hormone levels.
However, hypothyroidism can negatively affect the heart in a variety of ways.
Pericardial effusion, a condition characterized by excessive buildup of fluid in the sac around the heart, can result from hypothyroidism. Inflammation of the pericardium, as this sac around the heart is called, usually results in pericardial effusion. This inflammation can occur as a result of illness or injury and puts pressure on the heart. Heart function is impaired and can lead to heart failure or death. Treatment for pericardial effusion caused by hypothyroidism includes treatment of the thyroid and possibly anti-inflammatory drugs or surgery.
Hypothyroidism can cause the heart to enlarge. This condition can be due to an underlying medical problem, such as a thyroid problem. An enlarged heart, also called cardiomegaly, may not cause any symptoms. However, when symptoms do occur, they include shortness of breath and other difficulty breathing, dizziness, irregular heart rhythm, swelling, and coughing. Complications from cardiomegaly generally depend on the underlying cause. The greatest risk is the possibility of heart failure due to enlargement of the left side of the heart. Doctors treat cardiomegaly caused by hypothyroidism by restoring normal thyroid function.
Hypothyroidism can lead to heart disease. Mucin, a substance found in body tissues, accumulates abnormally in the body of a person with hypothyroidism. Mucin can cause swelling of the heart muscle. This leads to a weakening of the heart, which can cause both a decreased or increased heart rate and palpitations. Adults with severe hypothyroidism and those with high levels of thyroid hormone are at increased risk of developing heart failure.