The impact of hypothyroidism on the heart

The full name of hypothyroidism is hypothyroidism, which has a great impact on the heart. A disease caused by hypothyroidism is called hypothyroid heart disease. It is due to insufficient synthesis and secretion of thyroid hormone, which will cause weakened heart contractility, thereby inducing a more serious disease in patients. The incidence of this disease is relatively high in the elderly. Let's take a look at this aspect.

How does hypothyroidism affect the heart?

Hypothyroidism heart disease (HTC) is an endocrine disorder heart disease caused by insufficient synthesis, secretion or biological effect of thyroid hormone, which leads to weakened myocardial contractility, decreased cardiac output and peripheral blood flow, and a series of symptoms and signs.

This disease occurs in people of all age groups, most commonly in adults, but the relative incidence rate in the elderly is higher than in the younger group. Hypothyroidism in the elderly has an insidious onset and slow progression. Sometimes, when it develops to the late stage, the clinical manifestations are not obvious. Only a small number of patients have characteristic clinical manifestations and signs, such as fatigue, dullness, depression, myalgia, constipation and dry skin.

Conventional treatment

(1) Thyroxine replacement therapy: The purpose is to correct hypothyroidism, improve myocardial metabolic disorders, and make heart disease recoverable. Patients with permanent hypothyroidism require lifelong replacement therapy. Thyroid hormone preparations include dried thyroid powder (tablets), levothyroxine (L-T4), and L-triiodothyronine (L-T3). Commonly used in China is dried thyroid powder (tablets), which comes from livestock thyroid glands. Its dosage standard is determined by measuring the iodine content, which cannot truly reflect the content of T4 and T3. Therefore, the content of T4 and T3 varies greatly, but T4 is the main component. Recently, imported levothyroxine (synthetic) has been supplied, which has a mild and long-lasting effect and is the most ideal preparation for hypothyroidism replacement therapy. Synthetic L-T3 has a strong effect and a short duration, but is seldom used due to its large side effects.

(2) Thyroid powder (tablets): This is the most commonly used preparation in China. It is advisable to start with a small dose to avoid increasing the burden on the heart. 15-30 mg every morning, then slowly increase by 15-30 mg/d every 2-3 weeks until effective. The usual dose is 90-120 mg/d. Generally, diuresis and swelling will appear first, and then symptoms such as stomach cold, fatigue and anorexia will improve or disappear. If tachycardia, arrhythmia, angina pectoris, sweating and excitement occur during the treatment, the dosage should be reduced or suspended. Adjustments can be made after the above symptoms disappear. The disadvantages of thyroid powder (tablets) are that the potency is unstable, the absorption in the intestine varies, and the effect is slow. The advantages are that it is cheap, easy to obtain and easy to store.

(3) Levothyroxine: There are two dosage forms: 50 μg and 100 μg. The onset of action is about 4 days and the duration is about 10 days. The initial dose is 20-25 μg, which is increased by 25-50 μg after 7-14 days, and then increased by 25-50 μg every 4 weeks. After the clinical symptoms are relieved, the dose is maintained for long-term use. The maintenance dose is generally 100 to 200 μg per day. It has a long and stable effect and is particularly suitable for chronic diseases.