Patient's question:
Children with mitral valve regurgitation were found to have mild mitral valve regurgitation this month. Is there any medication available? Current general condition: There are no other symptoms, but the child's breathing is slightly rough.Doctor's answer:
Non-rheumatic mitral regurgitation refers to mitral regurgitation caused by abnormalities in the mitral valve itself and its surrounding anatomical structures, such as the left atrium, valve leaflets, chordae tendineae, papillary muscles, and left ventricle, excluding rheumatic valve disease. The causes or etiologies of non-rheumatic mitral regurgitation are numerous, with the most common being mitral valve prolapse, papillary muscle dysfunction or chordae tendineae rupture, left atrial myxoma, calcification of the valve annulus, congenital valve malformations, infective endocarditis, and others. Depending on the severity, progression rate, and duration of mitral regurgitation, varying degrees of hemodynamic changes and clinical manifestations may occur. Below are introduced several common non-rheumatic mitral regurgitation diseases.Mitral Valve Prolapse Syndrome (Barlow Syndrome)
Mitral Valve Prolapse Syndrome, also known as Barlow Syndrome or the mitral click-murmur syndrome, refers to the prolapse of the mitral valve into the left atrium during left ventricular contraction, accompanied or not accompanied by mitral regurgitation, and can present a series of symptoms and signs clinically.
Etiology and Pathological Anatomy
This is a clinical syndrome that can be divided into two major categories based on etiology: primary and secondary. The etiology of primary mitral valve prolapse is unclear, and some patients have a family history, possibly being an autosomal dominant genetic disorder. The pathological anatomy primarily involves mucoid degeneration of the mitral valve tissue, accompanied by valve elongation and relaxation. It can be seen in Marfan syndrome. Secondary mitral valve prolapse can be seen in conditions such as coronary heart disease, congenital heart disease (ischemic secundum atrial septal defect), and others. Clinically, the diagnosis of this condition typically refers to primary mitral valve prolapse. If the mitral valve leaflets are elongated, they may prolapse into the left atrium during left ventricular contraction, forming mitral valve prolapse, which can easily affect the closure of the mitral valve and may be accompanied or not accompanied by mitral regurgitation.
Clinical Manifestations
1. Symptoms
Most patients are asymptomatic. Some patients may initially present with fatigue, dizziness, or palpitations. Chest pain is more common, often recurring and atypical, resembling angina but not typical. The location of chest pain is variable, and the duration varies. Nitrates may provide uncertain relief. In more severe cases, dyspnea or syncope may occur, and some patients may have neuro symptoms such as anxiety, mental abnormalities, or personality changes.
2. Signs
The typical finding on cardiac auscultation is a mid-to-late systolic non- click in the apical area, followed by a late systolic murmur, which is clearer in the left lateral decubitus position. The click and the subsequent systolic murmur may exist alone. The presence of a click alone suggests only mitral valve prolapse, caused by the sudden cessation of the valve leaflet's bulge toward the atrial surface and the tightening of the chordae tendineae. If a systolic murmur is also present, it indicates the presence of mitral regurgitation. If mitral valve prolapse is accompanied by moderate-to-severe regurgitation, left ventricular hypertrophy and left ventricular dysfunction may be present. Arrhythmias are common. In addition, there may be chest wall abnormalities such as a straight back or scoliosis.
Laboratory and Other Tests
1. Electrocardiogram
Approximately 2/3 of patients have electrocardiogram abnormalities, primarily involving ST segment and T wave abnormalities, prolonged Q-T interval, prominent U waves, atrial or ventricular arrhythmias, sinus node dysfunction, and AV block.
2. X-ray Examination
Mild cases may not show an enlarged heart shadow. In cases of more severe mitral regurgitation, left atrial and left ventricular enlargement may be present. Left ventriculography can clearly determine the number and location of prolapsed valve leaflets.
3. Echocardiography
M-mode echocardiography shows a hammock-like posterior protrusion of the mitral valve closure line (CD segment) in the mid-to-late systole. Two-dimensional echocardiography shows the anterior or posterior leaflet of the mitral valve protruding into the left atrium during systole, beyond the level of the mitral valve annulus. Doppler echocardiography, if mitral regurgitation is present, can detect a systolic turbulent flow spectrum in the left atrium. Two-dimensional color Doppler echocardiography can visualize mitral regurgitation and measure its volume.
Diagnosis
The presence of a mitral click and systolic murmur is very helpful for diagnosis. Combined with echocardiography, the diagnosis can be confirmed. If there is doubt, left ventriculography can be performed.
Treatment
Asymptomatic patients do not require treatment. Symptomatic patients should receive targeted treatment.
1. Arrhythmias
Arrhythmias may be a major factor or cause of sudden death. For frequent premature ventricular contractions and paroxysmal tachycardia, 30–60 mg of propranolol per day, taken three times orally, can be used. If ineffective, amiodarone 0.4–0.6 g per day or quinine 0.6–1.2 g per day, taken three times, can be used.
2. Chest Pain
If chest pain does not respond to propranolol, nifedipine or verapamil can be used.
3. Prevention of Infective Endocarditis
Antibiotics should be used for prophylactic treatment in cases such as tooth extraction, surgery, skin infection, urinary tract infection, or upper respiratory tract infection.
4. Severe Mitral Regurgitation
Valve replacement surgery may be considered.
Papillary Muscle Dysfunction
Papillary muscle dysfunction refers to the dysfunction of the papillary muscles attached to the chordae tendineae of the atrioventricular valve due to ischemia, necrosis, fibrosis, or other factors, leading to mitral regurgitation and mitral regurgitation.
Etiology and Pathophysiology
Many factors can cause papillary muscle dysfunction. Burch's etiological classification includes:
1. Papillary muscle ischemia.
2. Left ventricular dilation.
3. Non-ischemic atrophy of the papillary muscle.
4. Congenital abnormalities of the papillary muscle or chordae tendineae.
5. Endocardial diseases (endocarditis, elastic fiber hyperplasia).
6. Dilated or hypertrophic cardiomyopathy.
7. Destruction of coordination of papillary muscle contraction.
8. Papillary muscle or chordae tendineae rupture.
Papillary muscle dysfunction is more common in coronary heart disease, acute myocardial ischemia (angina, myocardial infarction), and chronic myocardial interstitial fibrosis. Acute ischemia or necrosis of the papillary muscle can lead to a reduction in the contractile function of part of the papillary muscle. The formation of ventricular aneurysms causes relative motion during systole, pulling the corresponding papillary muscles to pull the mitral valve leaflets toward the ventricular cavity. Papillary muscle rupture causes the mitral valve leaflets to lose their pulling force during ventricular contraction and to flip back into the left atrium, both of which can lead to severe mitral regurgitation and severe mitral regurgitation.
Clinical Manifestations
1. Symptoms
Mild cases may be asymptomatic. In cases of significant papillary muscle damage and large regurgitation, palpitations, shortness of breath, and cough may occur. Acute ischemia or chordae tendineae rupture leading to sudden large mitral regurgitation often results in acute pulmonary edema and cardiogenic shock.
2. Signs
The most important sign of this disease is a systolic murmur at the apex. Papillary muscle dysfunction accompanied by angina pectoris has systolic murmurs at the apex that vary with the recurrence of angina pectoris. The systolic murmur of acute papillary muscle rupture is sudden, full systolic, and rough, often accompanied by a diastolic gallop rhythm or fourth heart sound.
Laboratory and Other Tests
1. Electrocardiogram
ST-T changes may occur, but they are not specific. Involvement of the anterior papillary muscle is generally associated with anterior wall myocardial infarction, so ST-T changes appear in leads I, aVL, V5, and V6. Involvement of the posterior papillary muscle is more often associated with posterior or inferior wall myocardial infarction, and ST-T changes appear in leads II, III, and aVF.
2. Echocardiography
Two-dimensional echocardiography shows normal thickness and elasticity of the mitral valve leaflets, small valve orifice, increased distance between the mitral valve and the interventricular septum, and can detect whether the chordae tendineae are ruptured. Doppler echocardiography can detect the volume of regurgitation.
3. X-ray Examination
Left atrial and left ventricular enlargement are common. Left ventriculography can show mitral regurgitation.
Diagnosis
The diagnosis of acute papillary muscle dysfunction is based on:
1. Appearance of a grade III or higher systolic murmur at the apex after acute myocardial infarction or severe angina pectoris recurrence, radiating to the axilla.
2. The degree and nature of the systolic murmur (and systolic click) are variable, and may be accompanied by S3 gallop and fourth heart sound.
3. The systolic murmur can be weakened after inhaling isopropyl nitrite and enhanced during the squatting test.
4. Left ventriculography is the most valuable for diagnosis, and echocardiography is also helpful.
Treatment
1. Medical Treatment
Treating the underlying cause, such as improving myocardial blood supply in patients with coronary heart disease and relieving angina, is beneficial for the recovery of acute papillary muscle dysfunction. Vasodilators can be used in severe regurgitation with heart failure.
2. Surgical Treatment
In cases of severe mitral regurgitation with papillary muscle rupture or chronic papillary muscle chordae tendineae disease, valve replacement or mitral annular repair and papillary muscle suture may be considered. However, surgical mortality is high.
Calcification of the Mitral Valve Annulus (Calcificatio of Mitralvalvular Rig)
This is a degenerative change of the elderly, with calcium deposition in the fibrous muscle ring of the mitral valve. Severe cases can lead to mitral valve insufficiency and regurgitation.
Etiology
The pathogenesis is unclear, and it is more common in patients with atherosclerosis. It most commonly occurs on the ventricular surface of the posterior leaflet. The incidence in the elderly population of Western countries is approximately 0.5–10.0%. There is no exact data in China, but with the widespread use of echocardiography, it has been commonly discovered.
Clinical Manifestations
Determined by the degree of calcification of the valve. Mild cases show no clinical manifestations. Severe lesions show thickening and fixation of the valve annulus, which cannot shrink with ventricular contraction, leading to restricted mitral valve movement and potentially mitral regurgitation or stenosis. A systolic murmur can be heard in the apex and lower left sternal border, radiating to the base. This condition often coexists with degenerative changes of the sinus node and conduction system, leading to sinus bradycardia, AV block, or slow ventricular rate atrial fibrillation. In some patients, calcium sloughing from the valve annulus can form emboli, leading to embolism in different parts of the body, with the brain and retinal artery embolism being the most common.
Diagnosis
Mainly relies on X-ray and echocardiography. The chest X-ray can show calcification shadows at the mitral valve annulus. Two-dimensional echocardiography shows a highly reflective echo mass in front of the atrioventricular junction, moving in the same direction as the left posterior ventricular wall.
Treatment
Generally has no significant hemodynamic effects and may not require treatment. Symptomatic treatment can be provided for heart failure symptoms.
Heart Myxoma (Myxoma of the Heart)
Heart myxoma is the most common primary tumor of the heart, mostly benign, with malignant cases being rare. Myxoma can occur on the endocardial surface of any heart chamber, with 95% occurring in the atria, approximately 75% in the left atrium, 20% in the right atrium, and 2.5% in each ventricle. Left atrial myxomas often occur near the fossa ovale and are commonly clinically due to tumor obstruction of the mitral valve, leading to mitral valve stenosis or insufficiency. Myxomas can occur at any age but are most common in middle age, with a higher incidence in women.
Pathology
The size of the tumor varies, with most having a stalk connected to the atrium or ventricular wall. The appearance is diverse, with a glossy, translucent gelatinous appearance. The cut surface is solid, with patchy hemorrhagic areas and small cystic cavities filled with blood clots. Under the microscope, tumor cells are stellate, spindle-shaped, round, or irregular, scattered or arranged in bundles within a large amount of mucoid matrix. The nuclei are mostly mononuclear but can also be multinucleated giant cells. Myxomas are heterogeneous in cell morphology, with large nuclei, deep staining, visible nuclear division, and tumor cells that can infiltrate small blood vessels to form tumor emboli.
Clinical Manifestations
The clinical manifestations depend on the location, size, nature, and presence or length of the stalk of the tumor. A large, long-stemmed tumor is more likely to cause stenosis or insufficiency of the atrioventricular valve, leading to hemodynamic changes and a series of symptoms. A small, short-stemmed tumor may be asymptomatic for a long time.
1. Symptoms
(1) Obstruction symptoms
Early symptoms may include palpitations, shortness of breath, and reduced exercise tolerance. Left atrial myxomas obstructing pulmonary veins or the mitral valve can produce symptoms similar to mitral valve disease, such as pulmonary congestion symptoms; paroxysmal nocturnal dyspnea, hemoptysis, and sputum streaks. In severe cases, jugular venous distension, hepatomegaly, and lower limb edema may occur. Right atrial myxomas obstructing the inferior vena cava or the tricuspid valve can produce symptoms similar to pericardial effusion; jugular venous distension, hepatomegaly, and edema. The obstruction symptoms of this disease are characterized by recurrence with changes in posture. Recurrent dizziness and dyspnea related to posture may occur if the tumor suddenly obstructs the atrioventricular valve, causing a significant decrease in cardiac output, which can lead to sudden syncope or cardiac arrest.
(2) Embolism
Embolism can occur due to the detachment of myxoma fragments or thrombi from the surface of the tumor, affecting the systemic and pulmonary circulation. Approximately 40% of left atrial myxomas can cause embolism, while right atrial myxomas are less likely to cause embolism.
(3) Systemic symptoms
Mainly include fever, increased erythrocyte sedimentation rate, anemia, weight loss, and abnormal elevation of serum α2 and β globulins, which may be related to bleeding, necrosis, and inflammatory cell infiltration within the tumor.
2. Signs
(1) Changes in heart sounds
In left atrial myxomas, the following changes in heart sounds may occur:
① Increased first heart sound at the apex.
② Increased and split second heart sound of the pulmonary artery.
③ A to-and-fro sound in the lower left sternal segment can be heard, which can be transmitted to the apex and base, produced by the tumor being pushed into the left ventricle and suddenly stopping. Vibration of the ventricular wall or tumor stalk. In addition, a fourth heart sound can be heard in the precordium.
(2) Heart murmurs
The obstruction of the tumor to the mitral valve or tricuspid valve can form mitral valve or tricuspid valve stenosis. When the tumor enters the ventricular cavity, mitral valve or tricuspid valve insufficiency may occur. Insufficiency may be the result of the tumor interfering with valve closure or may be due to the tumor repeatedly contacting the valve, forming scars on the valve, similar to chronic rheumatic valve inflammation, or even causing chordae tendineae rupture. Therefore, in left atrial myxomas, a diastolic rumbling murmur can be heard at the apex, which is enhanced when lying on the left side and weakened when lying on the right side. Sometimes, a systolic murmur that changes with posture (mitral regurgitation) can be heard.
In right atrial myxomas, a systolic-diastolic frictional to-and-fro murmur can be heard at the 3–4 intercostal spaces of the left sternal border.
In left ventricular myxomas, a 3-grade ejection systolic murmur can be heard at the base, which is transmitted to the neck. In right ventricular myxomas, a 2–3 grade systolic murmur can be heard at the 2–3 intercostal spaces of the left sternal border.
Laboratory and Other Tests
1. Laboratory Tests
Anemia, increased erythrocyte sedimentation rate, and elevated serum protein electrophoresis α2 and β globulins.
2. Electrocardiogram
Changes in electrocardiogram may include atrial and ventricular enlargement, first- and second-degree AV block, incomplete right bundle branch block, or atrial fibrillation. In more severe cases, ST-T changes may occur.
3. X-ray Examination
In left atrial myxomas, pulmonary congestion and pulmonary artery segment protrusion, left atrial and right ventricular enlargement are present. In right atrial myxomas, the shadow of the superior vena cava is widened, and right atrial and right ventricular enlargement are present.
4. Echocardiography
In left atrial myxomas, abnormal reflective light clusters are seen in the left heart cavity, moving between the left atrium and left ventricle. During systole, they return to the left atrial cavity, and during diastole, they reach the mitral valve orifice and enter the left ventricle. The EF slope of the anterior mitral valve leaflet is reduced, and the left atrium is enlarged. In right atrial myxomas, abnormal reflective light clusters are seen in the right heart cavity, contracting in the right atrium during systole, and moving toward the right ventricle through the tricuspid valve during diastole or entering the right ventricular cavity through the tricuspid valve. Right atrial and right ventricular enlargement are present.
5. Cardiovascular Angiography
Selective pulmonary artery angiography, either cine or continuous filming, can reveal a filling defect shadow in the left atrium, indirectly confirming the presence of a tumor in the atrium. Right atrial myxomas are generally performed with cava or right atrial angiography, which can also reveal a filling defect shadow in the right atrium.
Diagnosis
The basis for diagnosis is:
1. Clinical characteristics; obstruction symptoms, changes in heart sounds and murmurs.
2. Echocardiography is currently the best method for diagnosing intracardiac myxomas, especially two-dimensional echocardiography, which can clearly show the contour and activity of the tumor.
3. Cardiovascular angiography shows intracardiac space-occupying lesions, but it has a certain rate of false positives, and with the availability of echocardiography, cardiovascular angiography is less commonly used.
Differential Diagnosis
Left atrial myxomas should be differentiated from mitral valve stenosis. Mitral valve stenosis is often accompanied by a loud opening snap, rarely a fourth heart sound, and murmurs do not change with posture, without a to-and-fro sound. If there is doubt, echocardiography can be performed for differentiation. Left atrial spherical thrombi are also easily confused with left atrial myxomas. In echocardiography, left atrial thrombi mostly appear on the posterior wall of the left atrium, and their abnormal reflective light clusters lack the characteristic of rapid movement with the cardiac cycle. Left atrial thrombi are often associated with mitral valve stenosis, and thus, abnormal reflective patterns of mitral valve movement can also be seen.
Right atrial myxomas should be differentiated from constrictive pericarditis, tricuspid valve stenosis, and pulmonary valve stenosis. The systolic-diastolic frictional to-and-fro murmur at the 3–4 intercostal spaces of the left sternal border, as well as the correlation of symptoms and murmurs with changes in posture, are valuable for differential diagnosis.
Treatment
This disease has the risk of sudden death, so suspected patients should be diagnosed as early as possible. After the diagnosis is confirmed, early cardiac tumor resection should be performed to obtain better results.