Is There a Connection Between Amiodarone and Hypothyroidism?
Hypothyroid heart disease (hypothyroidism) is an endocrine disorder with a series of symptoms and signs such as reduced myocardial contractility due to insufficient thyroid hormone synthesis, insufficient secretion, or insufficient biological effects. Sexual heart disease. This disease is seen in all age groups, and is more common in adults, but the relative incidence of elderly people is higher than that of young people. The onset of hypothyroidism in the elderly is hidden, progresses slowly, and sometimes progresses to advanced stages, and clinical manifestations are not obvious. Only a few patients have characteristic clinical manifestations and signs, such as fatigue, dullness, depression, myalgia, constipation, and dry skin.
- Chinese name
- Hypothyroid heart disease
- Department
- Cardiology
- Hypothyroid heart disease (hypothyroidism) is an endocrine disorder with a series of symptoms and signs such as reduced myocardial contractility due to insufficient thyroid hormone synthesis, insufficient secretion, or insufficient biological effects. Sexual heart disease. This disease is seen in all age groups, and is more common in adults, but the relative incidence of elderly people is higher than that of young people. The onset of hypothyroidism in the elderly is hidden, progresses slowly, and sometimes progresses to advanced stages, and clinical manifestations are not obvious. Only a few patients have characteristic clinical manifestations and signs, such as fatigue, dullness, depression, myalgia, constipation, and dry skin.
Epidemiology of hypothyroid heart disease
- This disease is seen in all age groups, and it is more common in adults. However, the relative incidence of elderly people is higher than that of young people. In the literature, the prevalence of clinical hypothyroidism is 1% to 5% in elderly people> 65 years of age. Another 5% to 15% of the population is associated with subclinical hypothyroidism, and its prevalence increases with age. The prevalence is higher in hospitalized patients, and the prevalence of women is significantly higher than that of men, about 5: 1. . Statistics abroad show that the incidence of obvious hypothyroidism in the age group> 65 years is 2% to 5%, and there are more women than men, while mild or subclinical hypothyroidism accounts for 5% to 14 years in the age group> 65 years. %, It can be seen that the disease is not uncommon in the elderly, coupled with the slow onset, clinical symptoms are not typical, and easy to lead to missed diagnosis or misdiagnosis, you should be alert.
Pathogenesis of hypothyroid heart disease
- The causes of hypothyroidism are very complicated. According to its origin, clinical hypothyroidism is divided into three categories (Table 1): The hypofunction caused by thyroid disease is called primary hypothyroidism or hypothyroidism, which accounts for hypothyroidism. 90% to 95%. Hypothyroidism due to pituitary and hypothalamic lesions is central hypothyroidism or secondary and tertiary hypothyroidism. Caused by TSH or thyroid hormone resistance is called receptor or peripheral hypothyroidism. Among the various types of hypothyroidism, adult and juvenile hypothyroidism can be either primary to thyroid lesions or secondary to pituitary or hypothalamic lesions. Minor illnesses are mainly primary hypothyroidism.
Diagnosis of hypothyroid heart disease
- Those who meet the following 4 conditions can be diagnosed with hypothyroidism:
- 1. Meet the diagnostic criteria for hypothyroidism.
- 2. Enlarged heart, abnormal pericardial effusion, heart failure and electrocardiogram.
- 3. Exclude heart disease for other reasons.
- 4. Significantly improved or even recovered after thyroid hormone replacement therapy.
- Because the slow onset of hypothyroidism in the elderly is not typical, many symptoms are often attributed to senile changes without attention, and changes in the cardiovascular system are similar to heart disease, coronary heart disease or high heart disease, so it is easy to be misdiagnosed. Therefore, the elderly, especially women, with unexplained enlargement of the heart, pericardial effusion and electrocardiogram with QRS low voltage and unpleasant heart rate, should consider the possibility of hypothyroidism and need to be checked accordingly.
Differential diagnosis of hypothyroid heart disease
- 1. The differentiation of low thyroid hormone syndrome mainly needs to be different from that of T3 syndrome and adrenal insufficiency.
- 2. Identification of the cause of hypothyroidism, that is, to distinguish between primary, central and peripheral hypothyroidism.
- 3. The identification of hypothyroidism and subclinical hypothyroidism is mainly determined based on the results of FT3, FT4 and TSH.
- 4. The identification of common symptoms of hypothyroidism mainly includes edema, anemia, hypertension, serous fluid and abnormal liver function.
- 5. Identification with other systemic diseases such as delayed puberty, pituitary dwarfism, nephrotic syndrome, coronary heart disease, and pituitary tumors.
Treatment of hypothyroid heart disease
- Routine treatment
- (1) Thyroxine replacement therapy: The purpose is to correct hypothyroidism, improve myocardial metabolic disorders, and restore heart disease. Permanent hypothyroidism requires lifelong replacement therapy. Thyroid hormone preparations include dried thyroid powder (tablets), levothyroxine (L-T4), and L-triiodothyronine (L-T3). The dry thyroid powder (tablet) commonly used in China is derived from the thyroid of domestic animals. The dosage standard is determined by measuring the iodine content. It cannot truly reflect the content of T4 and T3. Therefore, the contents of T4 and T3 are quite different. T4-based; recently imported levothyroxine (synthetic) has been supplied, with a mild and long-lasting effect. It is the most ideal preparation for hypothyroidism replacement therapy. L-T3 is a synthetic agent with strong effect and short duration. Less applied.
- (2) Thyroid powder (tablet): It is the most commonly used preparation in China and it is advisable to start with a small dose to avoid increasing the burden on the heart. 15 to 30 mg every morning, and then slowly increase 15 to 30 mg / d every 2 to 3 weeks until it works. The usual dose is 90 to 120 mg / d. Generally diuresis and swelling first, followed by improvement or disappearance of symptoms such as cold stomach, fatigue and anorexia. If tachycardia, arrhythmia, angina pectoris, sweating, and excitement occur during treatment, it is advisable to reduce or suspend, and then adjust after the above symptoms disappear. The disadvantage of thyroid powder (tablet) is that the potency is unstable, the intestinal absorption varies, and the effect is slow. The advantage is that it is cheap and easy to obtain and easy to save.
- (3) Levothyroxine: The dosage forms are 50 g and 100 g, and the onset time is about 4 days and the duration is about 10 days. The initial dose is 20 to 25 g, which is increased by 25 to 50 g after 7 to 14 days, and thereafter increased by 25 to 50 g every 4 weeks. After the clinical symptoms are alleviated, the dose is maintained for a long time. The maintenance dose is generally 100-200 g per day, especially the long-term and stable effect, which is especially suitable for chronic diseases.
- 2. Treatment of cardiovascular disease
- (1) Angina pectoris: symptomatic treatment with nitroglycerin and its long-acting preparations. Severe angina pectoris in elderly patients without hypothyroidism is difficult to treat. Because thyroxine replacement therapy can aggravate angina pectoris, and beta-blockers commonly used to treat angina pectoris can cause severe sinus bradycardia. Coronary angiography in these patients often reveals severe lesions. Percutaneous coronary angioplasty (PTCA) or low-dose thyroxine can be used for coronary artery bypass grafting. Sufficient thyroid hormone replacement can be used after surgery. No more angina.
- (2) Heart failure: Digitalis preparation can be added at the same time as thyroxine replacement therapy. Digitalis has a prolonged half-life in the body, coupled with myocardial fibrous mucus edema, which changes its response to digitalis, so it is often ineffective and susceptible to poisoning. A small amount of caution is required.
- (3) Pericardial effusion: Because clinical symptoms are not obvious, pericardial tamponade rarely occurs, and most of them can be absorbed and subsided after replacement with thyroxine, so puncture and aspiration are generally not required. For those who have obvious symptoms of tamponade, or whose thyroid function has improved and there is still a lot of pericardial effusion, pericardial puncture and drainage or pericardial incision and drainage can be performed.
- (4) Hypertension: Use antihypertensive drugs with caution at the beginning of treatment. It is reported that thyroxine alone can restore blood pressure to 1/3 of patients. Antihypertensive drugs are considered for those with high blood pressure after thyroid function returns to normal.
- Those who fail to diagnose and treat in time can be ill for many years and eventually die of hypothyroidism coma, infection or cardiac complications. After effective treatment, clinical symptoms can be significantly improved, and heart disease progress is particularly significant. After 1 month of treatment, the heart can shrink significantly, and the electrocardiogram can return to normal within 4 to 6 weeks.
Complications of hypothyroid heart disease
- Concurrent pericardial effusion is common. A small number of myocardial oxygen consumption increased after treatment, but induced angina and myocardial infarction.
Prognosis of hypothyroid heart disease
- Elderly hypothyroid heart disease directly affects the application of thyroid hormones and has a negative prognosis. In addition to hypothyroidism, elderly patients may have hypothermia, coma, or even shock. The mortality rate can reach 50%.
Prevention of hypothyroid heart disease
- 1. Primary prevention through the prevention of various causes to prevent hypothyroidism, including prevention of Hashimoto's thyroiditis, avoiding iodine deficiency or excessive iodine, appropriate radioactive iodine treatment of Graves disease, avoiding excessive antithyroid drugs, and Other drugs that can cause hypothyroidism, such as prolonged overdose of aminosalicylic acid, buta pine, potassium perate, cobalt, lithium, and amiodarone. In recent years, amiodarone has been quite common in treating arrhythmias in the elderly. Amiodarone has three effects on thyroid function: first, by combining with thyroid receptors in the nucleus to fight the effect of thyroxine; second, by inhibiting the periphery T4 is converted to T3, so long-term medication can reduce serum T3 levels and transient TSH; third, the drug contains 35% iodine (by weight), which produces a large amount of inorganic iodine during metabolism in the body, leading to thyroid Inhibition of organic iodination. Hypothyroidism may occur in patients taking this drug (more common in the United States), and it has been reported frequently in the country. Therefore, for elderly patients taking amiodarone for a long time, the thyroid function should be regularly reviewed.
- 2.Secondary prevention is detected early, and regular (half a year to one year) physical examination is very important for diagnosing sick elderly people, especially for receiving radioactive iodine treatment and taking antithyroid drugs or taking p-aminosalicylic acid, butapine, over ammonia High-risk elderly people with potassium acid and amiodarone should regularly perform thyroid function measurement (3 months to 6 months).
- 3. Tertiary prevention For elderly patients with a clear diagnosis, thyroxine replacement therapy should be given to reduce the disability rate, hypothyroidism coma, and the incidence of cardiac complications. In elderly patients with hypothyroidism, if the course is long, the heart performance is very prominent, the incidence rate is 70% to 80%. In addition to sinus bradycardia, there is still an enlarged heart, pericardial effusion, distant heart sounds, and increased blood pressure. Complicated atherosclerosis is often similar to hypertension, coronary heart disease or cardiomyopathy, which is easy to be misdiagnosed, leading to untimely treatment and sometimes life-threatening. Once diagnosed and treated in time, the prognosis is good.
Examination of hypothyroid heart disease
- Blood lipids
- 2. Thyroid function tests, such as iodine intake and thyroid hormone determination.
- 3. Chest radiograph, echocardiogram, electrocardiogram.
Hypothyroid heart disease
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