Mitral valve stenosis

Introduction to mitral stenosis Rheumatic fever is the most common cause of clinical mitral stenosis (mitralstenosis). Repeated rheumatic fever repeated to form chronic rheumatic heart disease, which accounts for 95% to 98% of the mitral valve, of which simple mitral valve disease accounts for 70% to 80%, mitral valve combined with aortic valve disease 20% to 30%; more with mitral or aortic valve lesions. Simple mitral stenosis accounts for more than half of mitral valve disease (52%). basic knowledge The proportion of illness: 0.003% Susceptible people: no special people Mode of infection: non-infectious Complications: arrhythmia congestive heart failure

Causes of mitral stenosis

Causes

Mitral stenosis is the most common type of rheumatic valvular disease, and 40% of patients have simple mitral stenosis. Due to recurrent rheumatic fever, the early mitral valve is mainly composed of edema at the valve junction and its basal edema, inflammation and neoplasm (exudate), and gradually due to fibrin deposition and fibrosis during the healing process. Adhesion, fusion, valve thickening, roughness, hardening, calcification, and shortening and mutual adhesion of the chordae tendine are formed at the junction of the anterior and posterior leaflets, limiting the valve's ability to move and opening, resulting in narrowing of the valve. Other common causes include senile mitral annulus or subarachnoid calcification, congenital stenosis, and connective tissue disease.

Pathophysiology

When the normal adult mitral valve opening is open, the valve area is about 4-6 cm2, and the long diameter of the valve is 3~3.5 cm. When the valve area is <2.5 cm2 or the long diameter of the valve is <1.2 cm, different degrees will appear. Clinical symptoms, clinically, according to the extent of the reduction of the valve area and the length of the long diameter, the mitral stenosis is divided into mild (2.5 ~ 1.5cm2; > 1.2cm), moderate (1.5 ~ 1.0cm2; 1.2 ~ 0.8) Cm) and severe (1.0 ~ 0.6cm2; <0.8cm) stenosis, according to the degree of stenosis corresponding to hemodynamic changes, the natural course of mitral stenosis can be divided into three phases:

1, left atrial compensatory period: mild, moderate mitral stenosis due to diastolic left atrial reflow to left ventricular blood flow obstruction, left atrial compensatory expansion and hypertrophy to enhance contractility, so that late diastolic atrial bloodshed The increase in volume delays the increase in the mean pressure of the left atrium.

2, left atrial exhaustion: as the mitral stenosis worsens, the left atrial compensatory enlargement, hypertrophy and contractility increase difficult to overcome the hemodynamic disorder caused by stenosis, then the left atrial pressure gradually increased, Following the influence of pulmonary venous return, the pulmonary vein and pulmonary capillary pressures are successively increased, the diameter of the tube is enlarged, and the lumen is congested. On the one hand, it can cause decreased lung compliance, respiratory function disorders and hypoxemia; When the pulmonary capillary pressure is significantly increased, plasma and even blood cells leak out of the capillaries. When lymphatic drainage is not timely, plasma and blood cells infiltrate into the alveoli, which can cause acute pulmonary edema and signs of acute left atrial failure.

3, right heart involvement period: long-term pulmonary congestion reduces lung compliance, reflex can cause pulmonary arteriolar spasm, contraction, leading to pulmonary hypertension, long-term pulmonary hypertension can further cause pulmonary intima intima and middle layer thickening, further vascular lumen Stenosis, aggravation of pulmonary hypertension, forming a vicious circle, pulmonary hypertension will inevitably increase the right ventricular afterload, so that the right ventricular wall thickening and right heart cavity enlargement, eventually leading to right heart failure, at this time, pulmonary congestion and left atrial failure symptoms are reduced.

Mitral stenosis prevention

Rheumatic heart disease can be prevented. If it can effectively control the infection of a chain pharyngitis, it will not get rheumatic fever, and rheumatic heart disease will not occur. The main preventive measures are:

1, primary prevention

Refers to the prevention of the first episode of rheumatic fever, the key is early diagnosis and treatment of methyl chain tonsillitis, where fever, sore throat or discomfort, headache, abdominal pain, pharyngeal congestion and tonsil secretions should be swallowed swab culture before treatment, Determine the presence or absence of a chain growth. If it is positive, start antibiotic treatment immediately.

In addition to penicillin allergy, penicillin should be the drug of choice for all patients, for the following reasons:

(1) All strains of Streptococcus hemolyticus are equally sensitive to penicillin.

(2) After 40 years of application, the average bacteriostatic and bactericidal concentration of penicillin against this bacterium did not change, still around 0.005 g/ml.

(3) There is no sign of resistance to penicillin.

(4) To date, no other antibiotics have been active against Streptococcal infections and the clinical effect is more than penicillin G.

(5) Penicillin is relatively inexpensive and has a narrow antibacterial spectrum, so it does not inhibit the normal flora, can avoid double infection, and has fewer side effects than other effective antibiotics. Benzathine penicillin is suitable for patients who cannot complete oral penicillin treatment for 10 days; Patients with RF personal history or family history; or geographical, socioeconomic environment in patients with high RF incidence, intramuscular injection of benzathine alone is more painful, injection with benzathine penicillin plus procaine penicillin injection is not painful, The dose of benzathine penicillin contained in the mixed injection should be: 600,000 U for patients <27 kg, 1.2 million U for patients with >27 kg, and 900,000 U for benzathine penicillin and 300,000 U for procaine penicillin for most small patients. The mixture can achieve good results, but this preparation is not suitable for adolescent or adult patients. For RF low-incidence areas, penicillin V can be treated orally. Penicillin V has acid stability and absorption, and penicillin blood is produced. The concentration is higher, for children and adults, the dose is 250mg, 3 times / d, a total of 10 days, must emphasize the importance of continuous medication for 10 days, even if the symptoms disappear after a few days of medication, should be served for 10 days, less In 10 days The effect is obviously reduced, but it can not increase the curative effect for more than 10 days. The curative effect of treating streptococcal pharyngitis is the same or almost the same as that of oral penicillin. For adults, the effect of 2 times/d is unreliable, 3~4 times/d. Good, but the maximum dose does not exceed 1g / d, followed by cephalosporin IV, VI 0.25g, 4 times / d, a total of 10 days, but can not be used for patients with penicillin anaphylactic shock, tetracycline has not been produced in China, sulfadiazine can not be removed Streptococcus can not be used to treat streptococcal angina, but continuous use of sulfadiazine is effective in preventing RF recurrence.

2, secondary prevention (the prevention of rheumatic fever recurrence)

Continuous antibiotic treatment is needed for patients with a clear history of rheumatic fever or existing rheumatic diseases to prevent recurrence of rheumatic fever.

(1) Precautionary period: Depending on the risk of recurrence, in general, people with upper respiratory tract infections, crowded living, poor medical conditions, and multiple episodes of history have a high risk of recurrence and a long time to prevent medication. On the contrary, it can be shortened appropriately. Patients with rheumatoid carditis have a relatively high risk of recurrence of carditis. They should receive long-term antibiotic prophylaxis until adult or lifelong prevention. On the contrary, patients who have not had rheumatic carditis have recurrence. The risk of involvement is low and antibiotic prophylaxis can be stopped in a few years. In general, prevention should last until at least 5 years after the patient reaches the twenties or the last rheumatic fever.

(2) Prevention plan: (for reference only, please consult the doctor for details)

1 intramuscular injection of benzathine penicillin G: a common solution is long-acting penicillin preparation benzathine penicillin G1.2 million U, intramuscular injection, once every 4 weeks, in acute RF high-risk countries and regions, and high-risk patients, preferably every 3 weeks muscle Note 1 time.

2 oral antibiotics: patients with low risk of RF recurrence, such as those who have reached the end of puberty or adolescence or at least 5 years without recurrent rheumatic fever, can be changed to oral antibiotic prophylaxis, according to the recommended doses:

A. Sulfadiazine: body weight > 27kg, dose 1.0g, 1 time / d, weight 27kg, 0.5g / d, side effects are light and rare, occasionally can cause white blood cell reduction, should check blood cell count every 2 weeks, Patients with advanced gestation are banned because sulfadiazine can cross the placental barrier and compete with the bilirubin in the fetus for albumin binding sites.

B. Penicillin V: The dose is 250mg, 2 times / d, the allergic reaction is the same as the intramuscular injection of penicillin, and the penicillin skin test should be used before use.

C. Erythromycin: 250mg, 2 times / d, suitable for allergic to penicillin and sulfa drugs.

D. Chinese medicine such as honeysuckle, berberine, astragalus, cork, dandelion, radix isatidis, and andrographis paniculata; Chinese patent medicines such as silver yellow tablets, Yinqiao tablets, anti-inflammatory tablets, silver yellow needles, etc. have good effects on hemolytic streptococcal infection, choose application.

According to a recent WH0 report, 33,651 patients with RF or RHD were enrolled in secondary prevention for treatment in 1986-1990, but only about 63.2% of patients completed secondary prevention, 95.7% of whom used long-acting penicillin. Intramuscular injection once, 2.1% oral penicillin, 0.1% sulfadiazine, 2.1% erythromycin, 0.3% of patients had adverse reactions to penicillin, 53 cases of RF recurrence, accounting for 0.4% of patients/year, if not prevented The recurrence rate of rheumatic fever is as high as 60% of patients per year.

Mitral stenosis complications Complications arrhythmia congestive heart failure

1, arrhythmia

Atrial fibrillation is more common, often from atrial premature contraction to atrial tachycardia, atrial flutter to paroxysmal atrial fibrillation, and then to persistent atrial fibrillation, the mechanism is due to increased left atrial pressure and rheumatic Fibrosis of the left atrial wall after atrial muscle inflammation, resulting in confusion of the left atrial muscle bundle, causing atrial muscle, atrial conduction beam in the refractory period and conduction velocity is significantly inconsistent, resulting in reentry dysfunction, atrial fibrillation can reduce the heart The amount of blood discharged can induce or aggravate heart failure. Chronic atrial fibrillation can reduce the blood supply of atrial muscles. After a long time, it can cause diffuse atrophy of the myocardium, making it difficult to convert atrial fibrillation into sinus rhythm.

2, congestive heart failure

Right ventricular failure is a common complication and the main cause of death in the later stage of the disease. Congestive heart failure occurs in about 50% to 75% of patients in the late stage of the disease. Respiratory tract infection is a common cause of heart failure, but in young female patients, pregnancy and childbirth. Often the main cause.

3, acute pulmonary edema

This is a serious and urgent complication of moderate to severe mitral stenosis, with a high mortality rate, often caused by severe physical activity, emotional agitation, infection, pregnancy or childbirth, rapid atrial fibrillation, etc. The left ventricular diastolic filling period is shortened and the left atrial pressure is increased, so that the pulmonary capillary pressure is increased, and the plasma easily penetrates into the interstitial space or the alveolar, causing acute pulmonary edema. The symptoms are rapid development of shortness of breath, and cannot be supine, cyanosis. Cough pink foamy sputum, both lungs are covered with wet sputum, sometimes with wheezing, the patient has a sense of death, can quickly develop to hypoxic coma and death.

4, thromboembolism

Before surgery, at least 20% of patients may experience this serious complication at a certain stage of the mitral stenosis. About 10% to 15% of patients may die, embolism may be related to cardiac output. The amount is negatively correlated, and is directly related to the patient's age and the size of the left atrial appendage. Systemic embolism can occur in 80% of patients with mitral stenosis and atrial fibrillation. If thromboembolism occurs in patients with sinus rhythm, transient atrial fibrillation should be considered. And the possibility of potentially infective endocarditis, the occurrence of thrombosis has nothing to do with the size of the valve orifice. In fact, embolization can be the first symptom of mitral stenosis, or it can occur in mild mitral stenosis, or even Before dyspnea, patients over the age of 35 with atrial fibrillation, especially with reduced cardiac output and left atrial appendage expansion is the most dangerous period for the formation of emboli, so it should be treated with preventive anticoagulation.

Among the patients with recent history of embolism, only a few people found a left atrial wall with a thrombus, so it seems that only fresh blood clots will fall off. 50% of thromboembolism is seen in the cerebral blood vessels. Coronary embolism can cause angina or myocardial infarction. Renal artery embolization can cause systemic hypertension. About 25% of patients with embolic complications can have multiple or multiple embolizations. A large thrombus in the left atrium can form a pedicle-like thrombus, although it is rare. However, in a specific position, the left atrial outflow tract can be suddenly aggravated, and even a sudden death can occur. A free floating floating thrombus in the left atrium can produce similar results. The above two conditions often have characteristics that change with body position and are very dangerous. Emergency surgery is often required.

5, lung infection

Mitral stenosis leads to pulmonary congestion, decreased lung compliance, bronchial mucosal swelling and ciliated epithelial dysfunction, pulmonary interstitial exudate often becomes a good medium for bacteria, and patients with mitral stenosis have low resistance, so it is easy Repeated respiratory infections, and lung infections can induce or aggravate heart failure.

6, infective endocarditis

Infective endocarditis is rare in simple mitral stenosis, especially in patients with severe stenosis, thickening, and atrial fibrillation, which may be due to atrial fibrillation, heart failure, or severe mitral stenosis. The blood flow velocity is slowed down and/or the pressure gradient is reduced, and turbulence and jet flow are less likely to occur, so that the jet effect and the Venturi effect are weak, which is not conducive to the formation of neoplasms, so infective endocarditis is rare, but With the widespread development of device examination and valve surgery in recent years, mitral stenosis with infective endocarditis has been reported occasionally.

Symptoms of mitral stenosis Common symptoms Oval hole closed incomplete apex 1st heart sounds hyperthyroidism sitting angina pectoris heart blood stasis blocked sigh after comfortable pericardial palpitations pink pink foam heart tremor

1, symptoms

Patients with mitral stenosis may have very different clinical manifestations due to the severity of stenosis, the speed of progression, living conditions, occupation, labor intensity and compensatory mechanism. The main clinical symptoms are:

(1) Difficulty breathing: When the mitral stenosis enters the left atrial exhaustion period, it may produce different degrees of dyspnea. In the early stage, it only occurs during severe physical labor or strenuous exercise. A little rest can be relieved, often causing the patient to pay attention. As the degree of mitral stenosis is aggravated, it is also irritated in daily life and even at rest. There is often a paroxysmal dyspnea at night, and the condition is further developed. It is often not possible to lie flat, and you need to take a semi-recumbent or a sitting breath. These symptoms are often exacerbated by infections (especially respiratory infections), tachycardia, agitation and atrial fibrillation.

(2) hemoptysis: the incidence rate is about 15% to 30%, more common in patients with severe mitral stenosis, can have the following conditions.

1 large hemoptysis: due to bronchial bronchial rupture of the bronchial submucosa, due to the presence of collateral circulation between the pulmonary vein and the bronchial vein, a sudden increase in pulmonary venous pressure can be transmitted to the bronchial venule, causing the latter to rupture, often due to Pregnancy or strenuous exercise induces a sudden increase in pulmonary venous pressure. The amount of bleeding can reach hundreds of milliliters. Because the pulmonary venous pressure drops after hemorrhage often terminates spontaneously, hemorrhagic shock rarely occurs, but suffocation caused by hemoptysis must be guarded. Mitral valve The hemoptysis caused by stenosis occurs in the early stage of pulmonary congestion, not the manifestation of pulmonary hypertension. Later, due to the thickening of the venous wall, large hemoptysis is rare.

2 Congestive hemoptysis: often a small amount of hemoptysis or blood stasis in the sputum, caused by rupture of the endobronchial microvascular or inter-alveolar capillaries.

3 pink foam sputum: is a characteristic manifestation of acute pulmonary edema combined with alveolar capillary rupture.

4 pulmonary infarction hemoptysis: mitral stenosis, especially long-term bed rest and atrial fibrillation, due to venous or right atrial thrombus detachment, can cause pulmonary embolism and hemoptysis, often with a dense dark red sputum.

5 chronic bronchitis with blood in the sputum: mitral stenosis in patients with bronchial mucosa often edema, easy to cause chronic bronchitis.

(3) cough: unless combined with respiratory infection or acute pulmonary edema, mostly dry cough, more common at night or after labor, increased venous return, aggravation of pulmonary congestion caused by cough reflex; sometimes due to the apparent enlargement of the left atrium compression of the left bronchus caused by irritation Dry cough, pulmonary congestion and bronchial mucosal edema and exudation, plus bronchial epithelial cells with cilia dysfunction, easily cause bronchial and pulmonary infections, at this time there may be cough.

(4) palpitations: often caused by arrhythmia such as atrial fibrillation, rapid atrial fibrillation can induce acute pulmonary edema, so that the original asymptomatic patients have difficulty breathing or make it worse, and force the patient to seek medical treatment.

(5) Chest pain: patients with mitral stenosis and severe pulmonary hypertension may have post-sternal or precordial pressure or chest tightness, which often lasts longer than angina, nitroglycerin is ineffective, and the mechanism of chest pain is unknown. After mitral stenosis Chest pain can disappear. In addition, mitral stenosis combined with rheumatic coronary arteritis, coronary embolism or pulmonary infarction can also cause chest pain, the elderly still need to pay attention to coronary heart disease.

(6) hoarseness: rare, the left atrium is significantly enlarged, bronchial lymphadenopathy and pulmonary artery expansion can oppress the left recurrent laryngeal nerve, causing hoarseness (Ortner syndrome).

(7) Other:

1 fatigue and weakness: due to mitral stenosis caused by decreased cardiac output.

2 dysphagia: caused by the enlarged left atrium compression of the esophagus.

3 If the left atrial wall thrombus falls: can cause arterial (brain and internal organs) embolism symptoms.

4 when the right heart is involved in right heart failure: due to gastrointestinal congestion and dysfunction, can cause loss of appetite, due to liver congestion and liver dysfunction can occur liver pain, liver, abdominal distension, lower extremity edema, weight loss and other performance.

2, signs

(1) Diastolic murmur in the apical region: the diastolic murmur in the apical region is the most important sign for the diagnosis of mitral stenosis. The vast majority of cases can be diagnosed with mitral stenosis. The typical feature is that it is often confined to the apical region. In the middle and late stage of diastolic, low-grade, progressive, rumbling-like murmur, sinus rhythm often has late diastolic (pre-systolic) murmur enhancement, and continues to the first heart sound (S1), when the atrial fibrillation occurs before the systolic enhancement disappears, two The diastolic murmur of the cusp stenosis is lightly pressed with the bell-shaped stethoscope to gently press the apical wall of the apex and the left side of the patient is most easily heard. For those with mild murmurs, exercise, cough, forced exhalation or inhalation of isoamyl nitrite may be used. Other methods make the noise increase. Under normal circumstances, the severity of mitral stenosis has a certain relationship with the diastolic murmur of the apical region, but the relationship between the two is not necessarily proportional. The loudness of the noise depends mainly on blood volume and blood passing through the stenosis. The flow velocity of the valve mouth is proportional to the degree of stenosis in a certain range, but the murmur is reduced when the stenosis is severe, and even the murmur is not heard, so-called "dumb mitral stenosis" This is due to a significant reduction in blood flow through the mitral valve. When mitral stenosis with atrial fibrillation (mostly heavier mitral stenosis), tachycardia or left atrial failure, the murmur is also reduced; After the heart function is improved and the heart rate is slowed down, the noise can be enhanced. In addition, the pulmonary hypertension is combined, the noise is also reduced when the leaflets are fixed, and the noise is enhanced when the cardiac output is increased.

Clinically, a small number of mitral stenosis can not hear the diastolic murmur, the so-called dumb mitral stenosis, although this situation can be seen in very mild mitral stenosis, but clinically refers to severe mitral stenosis and Pulmonary hypertension, the main reasons for this are:

1 The valve is severely stenotic (less than 1.0cm2), the valve is thickened and adhered, and the activity is weakened, so that the blood flow through the mitral valve orifice is slowed down, and the blood volume is reduced, so that the noise is extremely light or even inaudible.

2 pulmonary hypertension, the right ventricle is significantly enlarged, extremely clockwise transposition, forcing the left ventricle to shift to the left, affecting the murmur transmission of the mitral valve, in addition, some patients with mitral stenosis have significantly reduced mental function and/or merger Atrial fibrillation, tachycardia, can make the original diastolic murmur significantly weakened or disappear, and become a dumb mitral stenosis. With the improvement of heart function, arrhythmia correction or ventricular rate slowing, the murmur can reappear, occasionally, In mitral stenosis and aortic valve disease, due to increased left ventricular end-diastolic pressure, the left atrial ventricular intervalvular pressure difference is reduced, the apical period diastolic murmur can be weakened, disappear, other such as emphysema, a large number of pericardial effusion Etc. may also affect the noise transmission, and the sound produced by the lung lesions sometimes masks the diastolic murmur. At this time, the patient should pause the breathing and carefully auscultate. Although the apical mitral stenosis area does not hear the diastolic murmur, However, other signs of mitral stenosis may still exist, such as the first heart sound in the apical region, the mitral valve open slap sound, the second heart sound hyperthyroidism in the pulmonary valve area, Graham-Stell murmur And relative tricuspid regurgitation murmur, X-ray, echocardiography, electrocardiogram, etc. still have corresponding changes in mitral stenosis; clinically there may be pulmonary congestion, left atrial failure and/or right heart failure.

(2) The first heart sound (S1) hyperthyroidism and open flap sound: left atrial pressure increased during mitral stenosis, at the end of diastole, left atrium, there is still a large pressure difference between the rooms, plus left ventricular diastolic filling Decreased, the anterior mitral valve is in the lower position of the ventricular cavity. When the ventricle contracts, the leaflet suddenly closes rapidly, which can produce a slamming sample S1. The open flap sound is also called the mitral valve open slap sound. It is most easily heard in the 3rd, 4th intercostal or apical area of the left sternal border. It is a high-key, crisp, short and loud heart sound immediately after S2. The mechanism is that when the mitral stenosis occurs, the early diastolic left The atrial pressure gradient is large, and the anterior lobe of the narrow mitral valve is strongly pushed to the left ventricle by the left atrial high blood flow, but the sudden opening is blocked in the middle, causing the anterior leaf tension to suddenly increase, prompting the sudden opening of the valve leaflet. In recent years, after echocardiography confirmed that the mitral valve is open, suddenly and quickly closes, and then open again, the presence of S1 hyperthyroidism and open flap sound often indicates that the anterior mitral valve has better mobility and elasticity. For the diagnosis of diaphragm type mitral stenosis, the selection Percutaneous balloon mitral valvuloplasty is helpful, funnel-type mitral stenosis, the valve mouth is stiff and funnel-shaped, the valve loses its elasticity, so the apical area S1 is weakened, no open sound, and often accompanied by closure Incomplete systolic murmur.

(3) Pulmonary valve closing sound (P2) hyperthyroidism, S2 division: When mitral stenosis leads to pulmonary hypertension, P2 hyperthyroidism can occur, S2 splits, sometimes slaps, and the pulmonary artery can expand as the pulmonary hypertension progresses. In the pulmonary valve area, jet-like systolic murmurs and pulmonary jets (shrinking early clicks) can be heard. When the pulmonary artery is severely dilated, relative pulmonary regurgitation can occur, and early diastolic airing can occur in the aortic auscultation area. The murmur, Graham-Stell murmur, produces a relative tricuspid regurgitation when the mitral stenosis develops to the right heart, and systolic murmurs can be heard in the tricuspid auscultation area.

(4) Other signs:

1 The patient's cheeks are red and the lips are slightly twitched with a "mitral valve face".

2 In children or adolescents, there may be a anterior bulge in the anterior region with an ascending pulsation.

3 The apical area can touch the S1 and diastolic tremor.

4 Percussion in the heart can be pear-shaped to change the heart to the left when the right ventricle is enlarged.

5 When pulmonary congestion and pulmonary edema occur, the lungs can be smelled dry and wet.

6 When there is a right heart failure, there is a sign of large circulation congestion.

Examination of mitral stenosis

1, echocardiography (UCG)

UCG has a high specificity for the diagnosis of mitral stenosis. In addition to determining the presence or absence of mitral stenosis and valve area, it can help to understand the shape of the heart, determine the degree of valvular disease and determine the surgical approach. The changes before and after and the recurrence of mitral stenosis after surgery are also of great value.

(1) M-type UCG: mitral stenosis M-type UCG performance includes:

1 The EF slope of the anterior mitral regurgitation is significantly reduced: in patients with sinus rhythm, EA changes in a flat (or flat oblique) shape, ie, a sacral change. In mitral stenosis, the EF slope is often <50 min/s, and the echo of the valve leaf is increased due to valve thickening, calcification and/or fibrosis. It must be noted that although the EF slope reduction is a sensitive indicator for the diagnosis of mitral stenosis, it is not specific, but also seen in severe pulmonary hypertension, primary hypertrophic cardiomyopathy, aortic valve disease, decreased left ventricular compliance, and diastolic pressure. Higher conditions.

2 mitral anterior flap CE amplitude decreased: CE spacing represents the amplitude of the anterior flap closure and full opening during the cardiac cycle, reflecting the flexibility, elasticity and mobility of the valve. In the case of mitral stenosis, the CE amplitude is reduced. If the amplitude is <15mm, and the valve echo is obviously increased, the valve should have the calcification of the valve. The severe calcification should be prepared for valve replacement even if it is simple.

3 ECG Q wave and mitral anterior flap C point prolongation: When mitral stenosis, QC interval is often >80ms, which is due to the left ventricle and left atrial pressure intersection. The normal QC interval is 40 to 60 ms. For patients with mild to moderate mitral stenosis, the QC interval is often <100 ms. If the QC interval is >100 ms, most of them are severe stenosis.

4 mitral valve posterior curve changes: mitral stenosis, due to adhesion of the anterior and posterior valve junction, diastolic valve opening, the posterior valve is pulled forward by the anterior valve with large anterior valve area , in the same direction, different from normal people. However, in about 10% of cases, the anterior and posterior flaps of the mitral valve still showed anisotropic movement or horizontal movement, which should be noted.

5EE spacing reduction: EE spacing should be measured at the tip of the mitral valve, representing the maximum distance of diastolic valve opening, EE spacing is reduced when mitral stenosis.

6 other changes: including left atrial enlargement, the degree of increase is positively correlated with the severity of mitral stenosis. The right ventricle is enlarged, the pulmonary artery is widened, and the left ventricle is not large. In some cases, the ventricular septum and the posterior wall of the left ventricle move in the same direction during diastole.

(2) Two-dimensional UCG: The performance of two-dimensional UCG in mitral stenosis includes:

1 The left ventricular long-axis view of the anterior region of the anterior region shows thickening of the mitral valve leaf and enhanced echo: the activity is stiff and the tip of the valve is often nodular. The thickening of the leaflets is particularly evident at the tip of the cusps. The apex of the anterior and posterior lobes of the diastolic period cannot be separated, and the open activity is limited and delayed. The anterior valve body often has a dome shape that protrudes toward the left ventricular outflow tract, showing a "balloon-like" change. It is generally believed that the more pronounced the dome shape, the lighter the degree of stenosis, the better the elasticity of the valve: conversely, if the dome disappears and the plate is in motion, the stenosis is severe and the elasticity is significantly reduced. In real time, the posterior valvular tip is drawn into the left ventricular outflow tract by the anterior flap and moves in the same direction. In addition, the left atrium is enlarged, and its degree of increase is positively correlated with stenosis. Sometimes there is a wall thrombus in the left atrium.

2 The anterior mitral horizontal short-axis view of the anterior mitral valve showed nodular thickening at the edge of the mitral valve, the echo was enhanced, and the junction was fused. The diastolic valve mouth was fish-like or irregular, and the valve area was significantly reduced. .

3 The apical region and the lower four-chamber view of the xiphoid can help to observe the degree of involvement of the mitral valve and measure the size of each compartment.

(3) Doppler UCG: Continuous or pulsed Doppler placed the sampling volume in the mitral or left ventricular inflow tract, which can detect diastolic broadband spectrum - turbulence, maintaining high flow rates during diastole. The blood flow signal has two peaks representing the early diastolic and atrial systole, respectively. The blood flow type of the double peak is related to the pressure difference of the mitral valve. According to the pressure difference, the severity of the stenosis can be estimated. Color Doppler flow imaging showed diastolic mitral diastolic blood flow narrowing, the center showed an inverted color, surrounded by multi-color mosaic. The blood flow has different shapes and directions, and can be eccentric or divided into multiple blood streams to the left ventricle.

(4) Quantitative diagnosis: On the two-dimensional UCG, the narrow valve area can be directly measured by an electronic cursor; on the continuous Doppler spectrum, the pressure half time (PHT) is used to estimate the cusp The flap area; Doppler can also be used to measure the transvalvular pressure difference. If tricuspid regurgitation is combined, the tricuspid regurgitation spectrum can be used to estimate right ventricular pressure or pulmonary artery pressure. Semi-quantitative detection of valve regurgitation using spectral Doppler and/or color Doppler.

(5) transesophageal UCG: transesophageal UCG has a good acoustic window, using high-frequency probes, directly in the posterior left atrium, more accurate observation of the valve and its ancillary structures than conventional transthoracic wall UCG, especially in the detection of atrial thrombosis Advantage. The sensitivity of detecting left atrial thrombus by chest wall UCG is about 30% to 60%, while the sensitivity of transesophageal UCG is more than 90%.

The three-dimensional UCG developed in recent years can dynamically observe the mitral valve structure in three dimensions. The reconstructed three-dimensional image is intuitive and similar to the actual anatomical structure, which can better display the lesion of the valve and provide more reliable information for the operation.

2, X-ray inspection

X-ray findings are related to the degree of mitral stenosis and the stage of disease progression. Mild mitral stenosis, normal heart shadow. Moderately above the stenosis, the left atrial enlargement can be found during the examination, the pulmonary artery segment is prominent, the left bronchus is elevated, and the right ventricle can be enlarged. The posterior anterior position, the heart shadow is like a pear shape, called "mitral valve heart", the aortic node is slightly smaller; the right anterior oblique position swallowing examination can find that the dilated left atrium compresses the esophagus, causing it to shift backward; left front oblique The position examination is easy to find an increase in the right ventricle. The pulmonary manifestations of mitral stenosis are mainly pulmonary congestion, and the hilar shadow is obviously deepened. Due to the redistribution of pulmonary venous blood flow, the upper vascular shadow is often increased and the lower part is reduced; the pulmonary lymphatic vessels are dilated, in the posterior anterior and left anterior oblique positions. On the chest radiograph, there is a horizontal line shadow near the right lung and the rib angle, which is the Kerley B line. Occasionally, a linear shadow from the upper lobe to the hilar is seen, called the Kerley A line. As a result of long-term pulmonary congestion, a punctiform shadow of hemosiderin deposition can be seen in the lung field.

3, ECG

Mild mitral stenosis, ECG can be normal. Moderate and severe mitral stenosis, the earliest ECG changes are characteristic P-waves of left atrial enlargement, that is, P-wave broadening and bimodal, called mitral-valve P-wave (PII>0.12) s, V1Ptf <-0.3 mm·s, P electric axis is +45° to -30°). As the disease progresses, when combined pulmonary hypertension involves the right heart, there may be an electrocardiogram of right axis deviation and right ventricular hypertrophy. Arrhythmia is very common in patients with mitral stenosis. Early manifestations of atrial premature contraction, frequent and multi-source atrial premature contractions are often a precursor to atrial fibrillation, and atrial fibrillation often occurs when the left atrium is significantly enlarged.

4, cardiac catheterization

For patients with difficult diagnosis, it is necessary to consider cardiac catheterization. The main manifestations of cardiac catheterization are increased pressure in the right ventricle, pulmonary artery and pulmonary arterioles, increased resistance to pulmonary circulation, and decreased cardiac output. The left atrium, left ventricular pressure and transmitral pressure difference can be directly measured by interatrial septal puncture.

Diagnosis and differentiation of mitral stenosis

diagnosis

Typical mitral stenosis, according to its clinical manifestations, especially cardiac auscultation can make a qualitative diagnosis, experienced doctors can still assess the severity of mitral stenosis, but accurate quantitative diagnosis still depends on laboratory tests, currently diagnosed two The most effective auxiliary examination for stenosis is echocardiography, followed by X-ray examination, and electrocardiogram is only used as an auxiliary diagnosis. Invasive cardiac catheterization is currently rarely used.

Differential diagnosis

1. Relative mitral stenosis: Relative mitral stenosis is seen in severe anemia, hyperthyroidism, dilated cardiomyopathy, left-to-right shunt congenital heart disease, and severe simple mitral regurgitation. Under the diastolic period, the mitral valve blood flow increases, and the apical area is often audible and diastolic murmur, but the noise is softer, shorter, no diastolic tremor, no S1 hyperthyroidism, no open sound .

2, rheumatic valvular heart disease: acute rheumatic fever occurs in active mitral valvular inflammation, apical area diastolic murmur, known as Carey-Coombs murmur, the murmur is a soft diastolic early murmur, daily changes, The murmur is higher than that of the organic mitral stenosis, and this murmur can completely disappear due to the healing of rheumatic carditis.

3, severe aortic regurgitation: severe aortic regurgitation, anterior mitral valvular abdomen in the diastolic phase of the aortic regurgitation blood flow uplift, resulting in limited anterior mitral valve opening, causing relative Narrow, so often heard in the apical area, a soft, short diastolic mid-term murmur, called Austin-Flint murmur, weakened after inhalation of isoamyl nitrite (murmur enhancement in mitral stenosis), the murmur without S1 And open flap sound, but there is an increase in carotid pulsation, as well as peripheral vascular signs.

4, left atrial myxoma: left atrial myxoma can produce symptoms and signs similar to mitral stenosis, but its murmur often appears intermittently, with body position changes, generally no open flap sound: can be heard and tumor fluttering; Atrial fibrillation rarely occurs, but peripheral arterial embolism is easy to occur. UCG is extremely helpful in diagnosing this disease. It is characterized by a cloud-like light cluster with a marginal edge in the left atrium, with a relatively uniform echo and moderate intensity.

5. Constrictive pericarditis: When the pericardium of the left atrioventricular sulcus is narrowed, the left atrioventricular channel can be narrowed, the left atrium is enlarged, and there is a similar mitral stenosis, but the echocardiogram shows The valve is normal, and the corresponding pericardial constriction is densely echoed, or a disordered echo occurs between the two pericardiums.

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