Hyperthyroid heart disease

Introduction to hyperthyroid heart disease Hyperthyroidism refers to cardiac enlargement, cardiac insufficiency, atrial fibrillation, angina and even myocardial infarction caused by direct or indirect effects of thyroxine on the heart during hyperthyroidism, sick sinus syndrome and An endocrine and metabolic disorder of heart disease and a series of cardiovascular symptoms and signs, sometimes second only to the hyperthyroidism crisis, is an important cause of death in patients with hyperthyroidism. basic knowledge The proportion of illness: 0.012% Susceptible people: no special people Mode of infection: non-infectious Complications: angina pectoris myocardial infarction arteriosclerosis dysmenorrhea mitral valve prolapse syndrome

Cause of hyperthyroidism

Excessive hormone secretion (65%):

Hyperthyroidism is excessively secreted during hyperthyroidism, resulting in hypermetabolism, increased oxygen consumption, excessive heat production, and marked changes in hemodynamics to accommodate high metabolic status, which can dilate skin capillaries and systemic circulating blood volume. Increased by more than 10%; blood flow velocity is increased, venous return flow is increased, so cardiac load is greatly increased, long-term sustained overload of the heart, abnormal changes in function and morphology, modern compensatory cardiac hypertrophy, and finally heart failure, Mainly due to right heart failure, the reason is that the amount of blood return to the heart, pulmonary artery and right ventricular pressure increased significantly, plus the right ventricular myocardial reserve capacity is worse than the left ventricle.

1 There are thyroxine receptors on the inner side of myocardial cell membrane. Thyroxine can directly act on the myocardium, accelerate myocardial metabolism and oxygen consumption process; increase the storage of calcium in cardiomyocytes, increase the concentration of phosphate ions, creatine and calcium ions in myocardial fibers. The concentration of potassium ions is reduced, the refractory period of various myocardial fibers is shortened, and the threshold of excitation is lowered. This is a cause of atrial fibrillation and other arrhythmias in hyperthyroidism patients. 2 The metabolic process of the myocardium changes, and thyroid hormone can activate ATPase on cardiomyocytes. Increased cAMP, provokes the action of catecholamines, increases the sensitivity of cardiac beta receptors to catecholamines; increases sensitivity to hypoxia, leads to coronary spasm, transient embolism and microcirculatory disorders, etc., is the main cause of angina pectoris 3, the direct action of thyroxine can strengthen the heart activity, that is, the heart rate is accelerated, the myocardial contractility is enhanced and the myocardial oxygen consumption is increased, which has an adaptive significance at the beginning, but because the heart rate is continuously accelerated (including at rest), the heart Diastolic phase is significantly shortened, myocardial recovery is incomplete, long-term fatigue, myocardial hypoxia Increased sensitivity, resulting in myocardial contractility, long-term cardiac reserve capacity exhaustion, heart failure can occur, 4 thyroid hormones on the heart muscle, can cause certain pathological changes, such as lymphocytes and eosinophil infiltration in the myocardium , fat infiltration, fibrosis, and even focal ischemic necrosis, known as hyperthyroid cardiomyopathy, these pathological changes can cause hyperthyroidism, especially one of the causes of arrhythmia or conduction abnormalities.

Arrhythmia (10%):

Patients with increased sensitivity to adrenaline and catecholamines, tachycardia and arrhythmias can occur, causing hyperthyroidism.

Hyperthyroidism prevention

The key is to make an early diagnosis of hyperthyroidism and timely appropriate treatment. Patients with early signs of hyperthyroidism should be treated as soon as possible.

Hyperthyroid heart disease complications Complications angina pectoris myocardial infarction arteriosclerosis dysmenorrhea mitral valve prolapse syndrome

1. Angina and myocardial infarction

The incidence of hyperthyroidism complicated with angina is 0.5% to 20%, and even as high as 20% to 25%. It is more common in patients with severe hyperthyroidism and patients over 40 years old, but the youngest is only 18 years old, more women than men, and the myocardial oxygen consumption increases sharply. Inconsistent with oxygen transport, even in a quiet state, myocardial oxygen consumption in patients with hyperthyroidism is increased, therefore, patients with hyperthyroidism can develop quiet angina pectoris, hyperthyroidism with coronary heart disease should be careful when determining surgical treatment, because there are The possibility of myocardial infarction, hyperthyroid angina after treatment of hyperthyroidism, can generally disappear, a small number of patients still have angina.

Myocardial infarction rarely occurs in patients with hyperthyroidism. The reason is that there is no condition of arterial thrombosis. The lipid metabolism of hyperthyroidism patients is characterized by cholesterol, decreased levels of -lipoprotein and lecithin, increased lecithin/cholesterol index, and blood flow velocity during hyperthyroidism. Accelerated, blood coagulability decreased, anticoagulant system activity increased, hyperthyroidism accompanied by myocardial infarction, mainly seen in the elderly, the most common in patients with hyperthyroidism and arteriosclerosis.

2. Mitral valve prolapse (MVP)

The incidence of hyperthyroidism combined with MVP is extremely high, 42.5%. The reason is that both Graves disease and MVP may be hereditary diseases. The common cause of the two is immune system disorder. MVP is a common cardiac abnormality, which may be coupled with the two. Coexistence; hyperthyroidism in patients with hyperthyroidism, can cause local degeneration and inflammatory lesions of the heart, of course, can also involve the mitral valve, therefore, when hyperthyroidism patients have chest pain, shortness of breath or extreme anxiety and other neuropsychiatric symptoms, especially the precordial area Smell and non-ejection clicks, to be highly suspected of the presence of MVP, should be done UCG examination, the disease can disappear with the recovery of hyperthyroidism.

Hyperthyroidism Symptoms Common symptoms Arrhythmia Heart failure Chest heavy circulatory disorder Heart weight increased mitral valve prolapse palpitations with weight loss, diarrhea, hyperthyroidism, face metabolism, strong palms, sweating

1. Hyperthyroidism and arrhythmia

Hyperthyroidism is most common in hyperthyroidism, including sinus tachycardia, pre-atrial contraction, paroxysmal tachycardia, ventricular flutter, atrial fibrillation, the most common of which is atrial fibrillation, which is reported to be approximately 5%. ~15% of patients with hyperthyroidism complicated with atrial fibrillation, with an increase in the incidence of age, some patients can see atrial fibrillation as the only symptom to see a doctor, a large study suggests that nearly 1% of the newly occurring atrial fibrillation is caused by hyperthyroidism, and 13% of unexplained atrial fibrillation also has biochemical evidence of hyperthyroidism. Therefore, routine thyroid function tests should be performed on newly diagnosed atrial fibrillation to rule out hyperthyroidism. Occasionally, hyperthyroidism complicated with high atrioventricular block is likely to occur. It is related to myocardial histological changes caused by hyperthyroidism. Myocardium may have lymphocyte and eosinophilic infiltration and pathological changes of mitochondria. When these pathological changes affect the myocardial conduction system, atrioventricular block may occur.

The pathophysiological basis of hyperthyroidism is not fully understood. The formation of multiple reentry circuits is the basis of atrial fibrillation. The activity of Na-K-ATPase in cardiomyocytes is enhanced during hyperthyroidism, which promotes the outflow of Na. The influx of K affects the electrophysiology of cardiomyocytes. The most significant electrophysiological abnormality in experimental hyperthyroidism is that the action potential time of a single atrial myocyte is shortened, and as a result, the electrical excitability of the atrium is increased, and atrial fibrillation may occur.

2. Hyperthyroidism and heart enlargement

Long-standing untreated hyperthyroidism can cause prominent changes in heart shape, including atrial or ventricular enlargement, increased heart weight, cardiomyocyte hypertrophy, and widening of myocardial fibrosis. These changes can be improved or reversed after thyroid function returns to normal, hyperthyroidism increases Big reason:

1 High dynamic circulation state: T3, T4 rise caused significant hemodynamic changes, manifested as increased peripheral oxygen consumption in peripheral tissues and myocardium, increased circulating blood volume, increased cardiac output, and excessive long-term capacity overload of the heart. Heart enlargement;

2T3 elevation can directly promote the synthesis of myocardial protein and the growth of myocardial cells, causing cardiac hypertrophy;

3 The role of thyroid hormone can be independent or added to the action of catecholamines, increasing the sensitivity of endogenous catecholamines, causing cardiac hypertrophy through receptors;

4 The role of renin-angiotensin-aldosterone system (RAAS) and atrial natriuretic peptide (ANP), the vasodilatation of the surrounding tissue during hyperthyroidism, reducing renal blood flow, reducing the effective perfusion pressure, thereby activating RAAS, resulting in sodium retention Although the ANP is also elevated, it is not sufficient to fight the activated RAAS.

3. Hyperthyroidism and heart failure

According to reports, the incidence of congestive heart failure in patients with hyperthyroidism is about 6%, and the age is greater than 60 years. The older patients are more likely to occur. The occurrence of heart failure is related to the following factors:

1 hyperthyroidism when hyperthyroidism causes myocardial load to be overweight for a long time, which can cause heart enlargement and increase cardiac output;

2 myocardial oxygen consumption increased, energy metabolism disorders;

3 rapid arrhythmia, especially atrial fibrillation, decreased cardiac output;

4RAAS activation can lead to cardiac hypertrophy and increased blood volume. The heart failure is characterized by right heart failure and left heart failure. We have color Doppler echocardiography in 68 patients with hyperthyroidism who were hospitalized. Graph analysis showed that most patients showed bilateral atrial enlargement, more common in the left atrium, especially in patients with atrial fibrillation, left atrial enlargement, bilateral ventricular enlargement and large right ventricular enlargement; valvular regurgitation is common, although there are Right heart failure exists, but the heart failure ejection fraction (EF) can still be in the normal range, and rare refractory heart failure may be caused by autoimmune-related cardiomyopathy.

4. Angina and myocardial infarction

Hyperthyroidism has less angina pectoris, mostly coronary artery blood supply is relatively insufficient, chest or chest heavy feeling is more common, myocardial infarction is rare, associated with coronary spasm, microcirculatory disorders and hemorheology abnormalities.

Examination of hyperthyroidism

1. Thyroid suction 131I rate check

131I check the peak of iodine absorption and move forward.

2. Determination of thyroid hormone

Abnormality of thyroid function: elevated serum T3, T4, FT3, FT4, etc.

3. X-ray inspection

The heart is enlarged, the heart beats vigorously, the pulmonary artery arches out, and the heart is excitatory and highly motivated. The heart is enlarged. If there is long-term atrial fibrillation or heart failure, the heart shadow is enlarged. When there is severe heart failure, the heart shadow is on both sides. expand.

4. ECG examination

(1) Left ventricular hypertrophy: The electrocardiogram of left ventricular hypertrophy should be regarded as a sign of left ventricular debilitation. Therefore, heart failure may occur when hyperthyroidism patients have ECG changes.

(2) ST-T changes: ST-T pathological decline and T-wave changes (reduced, two-way, inverted) are mainly seen in severe hyperthyroidism. After effective treatment of hyperthyroidism, most ST-T changes can be alleviated or disappeared.

(3) Hyperthyroidism P wave: The electrocardiogram of patients with hyperthyroidism has a P wave change of 26.2%, and there may be "atypical pulmonary P wave" or low amplitude bimodal variant P wave in the II, III lead, called hyperthyroidism P. Waves, high P waves can occur in the early stage of hyperthyroidism, and the amplitude of disease progression is reduced.

(4) PQ interval change: PQ interval prolongation in hyperthyroidism was 1.7% to 4.6%, and it was also reported to be 5.5%. It is generally considered that this conduction delay is a functional change.

(5) High T wave: High amplitude T waves are common in mild hyperthyroidism, and the amplitude is reduced during the progression of the disease, and the high T wave is only 14%.

(6) QT interval: The prolongation of QT interval is more common than shortening.

Diagnosis and diagnosis of hyperthyroidism

Diagnostic criteria

Because the clinical manifestations of hyperthyroidism have no significant specificity, they are easily confused with other cardiovascular diseases, resulting in clinical misdiagnosis or missed diagnosis, especially in the elderly. On the one hand, patients have long-term cardiovascular history (such as Coronary heart disease, high heart disease or pulmonary heart disease, etc., and the typical symptoms of hyperthyroidism are absent, which masks the performance of hyperthyroidism, resulting in poor or even ineffective cardiovascular treatment, and also delays the treatment time of hyperthyroidism; On the one hand, patients with confirmed hyperthyroidism whose cardiovascular symptoms are caused by other diseases, but are misdiagnosed as hyperthyroidism, can also lead to a decrease in treatment effect and delay in treatment, causing physiology to the patient. Psychological and economic losses, comprehensive aspects, the diagnostic criteria for hyperthyroidism should include:

1 diagnosed as hyperthyroidism;

2 hyperthyroidism accompanied by one or more cardiac abnormalities; (including arrhythmia, heart enlargement, heart failure, mitral valve prolapse with heart disease rational murmur);

3 Exclude heart disease caused by other causes;

4 After regular anti-thyroid treatment, cardiovascular symptoms and signs basically disappeared.

Differential diagnosis

Coronary heart disease

Hyperthyroidism, especially in elderly patients with angina pectoris, atrial fibrillation and myocardial ischemia, are often misdiagnosed as coronary heart disease. Therefore, for the elderly with the diagnosis of coronary heart disease, although there is no typical or obvious For signs of hyperthyroidism, if there are any of the following conditions, further examinations should be made regarding hyperthyroidism:

(1) angina pectoris, electrocardiogram changes in atrial fibrillation or myocardial ischemia, no significant improvement in drug treatment such as crown expansion.

(2) Heart failure occurs after a long period of loss of labor.

(3) There is unexplained progressive weight loss, diarrhea or blood lipids are significantly reduced.

(4) There are signs of increased metabolism and sympathetic excitation.

(5) Symptoms associated with hyperthyroidism, such as hyperhidrosis, anxiety, excitement, insomnia (which is easily misdiagnosed as a manifestation of neurosis), and periodic paralysis or marked muscle weakness.

2. Atrial fibrillation

Hyperthyroidism is a long-term burden on the atrium, which is prone to atrial fibrillation. This is similar to the mechanism of atrial fibrillation in hypertensive mitral stenosis. Atrial fibrillation can also occur in other heart diseases such as coronary heart disease. Atrial fibrillation has the following characteristics: more common in patients with hyperthyroidism over 45 years old; initial paroxysmal, followed by sinus rhythm and paroxysmal atrial fibrillation alternately, and finally develop into persistent atrial fibrillation; The tremor is mostly rapid, the ventricular rate is much faster >130 beats/min, and the ventricular rate of coronary heart disease is often <130 beats/min; the response to digitalis is poor, and the general antiarrhythmic drug is invalid; the course is long; the drug or After surgical treatment of hyperthyroidism, atrial fibrillation can disappear. After the hyperthyroidism is controlled and the drug is still not lost, it is necessary to consider whether there is coronary heart disease. It is necessary to pay attention to all aspects of the diagnosis of hyperthyroidism, and to exclude or confirm other causes. Heart disease in atrial fibrillation can be identified.

3. Heart failure

Patients with heart failure with hyperthyroidism are mainly heart failure, and those with atrial fibrillation are prone to heart failure. In heart failure, due to enlarged heart, mitral regurgitation and stenosis may occur, which may be accompanied by apex. The regional diastolic murmur and the second heart sound in the pulmonary artery area are often misdiagnosed as rheumatic heart disease mitral valve disease, tricuspid regurgitation and the like.

4. Rheumatic heart disease

Patients with hyperthyroidism have no tremor at the apex of the apex, systolic murmurs can be heard in the apex of the apex, the pulmonary artery area is louder, the apex of the apex is not transmitted to the underarm, and there is little diastolic murmur, and generally no pulmonary infection, acute pulmonary edema, Complications such as bacterial endocarditis are not good for digitalis, but rheumatoid heart disease is the opposite.

Although most patients with hyperthyroidism have diastolic murmurs, a small number of patients may have diastolic murmurs, which are differentiated from patients with mitral stenosis.

5. Other

Such as hyperthyroidism when metabolism is strong, may have tachycardia and hypothermia symptoms, and due to hypercatalytic hyperactivity, joint pain and other symptoms, can be misdiagnosed as rheumatic fever; hyperthyroidism when the body oxygen consumption increased, sometimes due to myopathy caused by respiratory muscles Inability to develop chest tightness, shortness of breath, difficulty breathing, etc., can also be misdiagnosed as pulmonary heart disease; systolic murmur of the left sternal border or bottom of the heart when hyperthyroidism, such as accompanied by hyperthyroidism, such as clubbing (toe), Can also be misdiagnosed as congenital heart disease; hyperthyroidism is prone to arrhythmia, such as supraventricular tachycardia, atrial fibrillation, early room, occasionally ECG manifestation of pre-excitation syndrome, and misdiagnosed as pre-excitation syndrome; indifferent hyperthyroidism The clinical manifestations are similar to hypothyroidism. This type of hyperthyroidism is associated with hyperthyroidism and is easily misdiagnosed as various types of heart disease. Therefore, to improve the alertness to hyperthyroidism, the symptoms of multiple systems should be serious. Comprehensive analysis to reduce misdiagnosis.

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