Children mitral regurgitation

Patient's question:

Children mitral regurgitation This month a mild mitral regurgitation was detected, please ask if there is any medication. Currently general condition: Currently no other symptoms, the child's breathing is a bit rough.

Doctor's answer:

Non-rheumatic mitral regurgitation refers to mitral regurgitation caused by abnormalities of 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 degree, 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 a series of symptoms and signs may appear clinically.
Etiology and Pathology
This is a clinical syndrome that can be divided into two major categories—primary and secondary—based on etiology. The etiology of primary mitral valve prolapse is unclear, and some patients have a family history, possibly being an autosomal dominant genetic disorder. The main pathological changes include mucoid degeneration of the mitral valve tissue, along with 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 and congenital heart disease (ischemia of the secundum type atrial septal defect). Clinically, the diagnosis of this condition typically refers to primary mitral valve prolapse. Mitral valve leaflet elongation can prolapse into the left atrium during left ventricular contraction, forming mitral valve prolapse, which can easily affect mitral valve closure and may or may not be accompanied by mitral regurgitation.
Clinical Manifestations
1. Symptoms
Most patients are asymptomatic. Some patients may initially present with fatigue, dizziness, and palpitations. Chest pain is more common, often recurrent and atypical, resembling angina but not typical. The location of chest pain is variable, with varying durations of pain, and nitrate medications may not be effective. Severe cases may develop dyspnea or syncope, 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 at the apex, 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 isolated 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 signs of left ventricular dysfunction may be present. Arrhythmias are common. In addition, there may be chest deformities such as a straight back or scoliosis.
Laboratory and Other Tests
1. Electrocardiogram
About two-thirds of patients have electrocardiogram abnormalities, primarily 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 significant changes in cardiac size. In cases of more severe mitral regurgitation, left atrial and left ventricular enlargement may be present. Left ventriculography can clearly demonstrate 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 mitral valve leaflet prolapsing into the left atrium, exceeding the level of the mitral valve annulus. Doppler echocardiography, if mitral regurgitation is present, can detect systolic turbulent flow spectra in the left atrium. Two-dimensional color Doppler echocardiography can map mitral regurgitation and measure its volume.
Diagnosis
The presence of a mitral click and systolic murmur is very helpful for diagnosis, and echocardiography can confirm the diagnosis. For cases with suspected diagnosis, left ventriculography may 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/day of propranolol can be administered in divided doses. If ineffective, amiodarone (0.4–0.6 g/day) or quinine (0.6–1.2 g/day) can be used in divided doses.
2. Chest Pain
If chest pain is not relieved by propranolol, nifedipine or verapamil can be used.
3. Prevention of Infective Endocarditis
Prophylactic antibiotics should be used for procedures such as tooth extraction, surgery, skin infections, urinary tract infections, and upper respiratory tract infections.
4. Severe Mitral Regurgitation
Valve replacement surgery may be considered.
Papillary Muscle Dysfunction
Papillary muscle dysfunction refers to the impaired contraction function of the papillary muscles attached to the chordae tendineae due to factors such as ischemia, necrosis, fibrosis, or other etiologies, leading to mitral regurgitation and mitral regurgitation.
Etiology and Pathophysiology
There are many factors or etiologies that 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 papillary muscle contraction coordination.
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 partial dysfunction of the papillary muscle's contraction function. The formation of ventricular aneurysms causes relative motion during systole, pulling the corresponding papillary muscles to pull the mitral valve leaflets back into the ventricular cavity, and rupture of the papillary muscle causes the mitral valve leaflets to lose traction force during systole and flip back into the left atrium, all of which can lead to severe mitral regurgitation and significant mitral regurgitation.
Clinical Manifestations
1. Symptoms
Mild cases may be asymptomatic. In cases of significant papillary muscle damage and large regurgitant volume, palpitations, dyspnea, 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 is a systolic murmur at the apex. Papillary muscle dysfunction accompanied by angina pectoris may have 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. Anterior papillary muscle involvement is generally associated with anterior wall myocardial infarction, so ST-T changes appear in leads I, aVL, V5, and V6. Posterior papillary muscle involvement 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 regurgitant volume.
3. X-ray Examination
Left atrial and left ventricular enlargement are common, and left ventriculography can show mitral regurgitation.
Diagnosis
The diagnosis of acute papillary muscle dysfunction is based on:
1. The 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 systolic murmur (and systolic click) varies in degree and nature, and may have 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 annulus repair and papillary muscle suture may be considered, but surgical mortality is high.
Calcification of the Mitral Valve Annulus (Calcification of the Mitral Valve Ring)
This is a degenerative change associated with aging, where calcium deposits in the fibromuscular 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 frequently occurs on the ventricular surface of the posterior leaflet. The incidence in the elderly population of Western countries is approximately 0.5–10.0%, and there is no exact data in China, but with the widespread use of echocardiography, it is commonly detected.
Clinical Manifestations
Determined by the degree of calcification of the valve. Mild cases show no clinical manifestations. Severe cases show thickening and rigidity 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 at the apex and lower left sternal border, radiating to the base of the heart. This condition often coexists with degenerative changes in the sinus node and conduction system, leading to sinus bradycardia, AV block, and slow-rate atrial fibrillation. In some patients, calcium debris from the valve annulus may form emboli, leading to embolism in different parts of the body, with the brain and retinal artery being the most common sites.
Diagnosis
Mainly relies on X-ray and echocardiography. X-ray chest films can show calcification of 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 cardiac tumor and is 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% each in the left and right ventricles. Left atrial myxomas often occur near the fossa ovalis 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 atrial 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 have varying cell morphologies, with large nuclei, deep staining, and visible nuclear division. Tumor cells 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. Tumors with long stalks are more likely to cause stenosis or insufficiency of the atrioventricular valve, leading to hemodynamic changes and a series of symptoms. Tumors with short stalks may be asymptomatic for a long time.
1. Symptoms
(1) Obstruction symptoms
Early symptoms may include palpitations, dyspnea, and reduced exercise tolerance. Left atrial myxomas obstructing pulmonary veins or the mitral valve can produce pulmonary congestion symptoms similar to mitral valve disease; paroxysmal nocturnal dyspnea, hemoptysis, and sputum streaks. Severe cases may have jugular venous distension, hepatomegaly, and lower limb edema. Right atrial myxomas obstructing the inferior vena cava or tricuspid valve can produce symptoms similar to pericardial effusion; jugular venous distension, hepatomegaly, and edema. Obstruction symptoms of this disease have the characteristic of recurrence with changes in body position, such as recurrent dizziness and dyspnea related to body position. If the tumor suddenly obstructs the atrioventricular valve, causing a significant decrease in cardiac output, sudden syncope or cardiac arrest may occur.
(2) Embolism
Fragments of the myxoma or thrombi on the surface of the tumor can embolize to the systemic or pulmonary circulation. About 40% of left atrial myxomas can cause embolism, while embolism is less common in right atrial myxomas.
(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 may be present:
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 of the heart, produced by the tumor being pushed suddenly to the left ventricle and 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 tumor obstructing the mitral valve or tricuspid valve can cause mitral valve or tricuspid valve stenosis. When the tumor enters the ventricular cavity, mitral valve or tricuspid valve insufficiency may appear. 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, which resemble chronic rheumatic valve inflammation or even cause chordae tendineae rupture. Therefore, in left atrial myxomas, a diastolic rumbling murmur can be heard at the apex, which is enhanced in the left lateral decubitus position and weakened in the right lateral decubitus position. Sometimes, a systolic murmur that changes with body position (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 3rd-degree ejection systolic murmur can be heard at the base of the heart, radiating 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 the electrocardiogram may include atrial and ventricular enlargement, 1st-degree AV block, incomplete right bundle branch block, or atrial fibrillation. Severe cases may have ST-T changes.
3. X-ray Examination
In left atrial myxomas, there is pulmonary congestion and a prominent pulmonary artery segment, with left atrial and right ventricular enlargement. In right atrial myxomas, the shadow of the superior vena cava is widened, with right atrial and right ventricular enlargement.
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, with systolic movement in the right atrium and diastolic movement toward the right ventricle through the tricuspid valve or entering the right ventricular cavity. Right atrial and right ventricular enlargement.
5. Cardiovascular Angiography
Selective pulmonary artery angiography or cineangiography 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 diagnosis is based on:
1. Clinical features; obstruction symptoms, changes in heart sounds and murmurs.
2. Echocardiography is currently the best method for diagnosing cardiac myxomas, especially two-dimensional echocardiography, which can clearly show the contour and movement of the tumor.
3. Cardiovascular angiography shows intracardiac occupying lesions, but it has a certain rate of false positives, and with the availability of echocardiography, cardiovascular angiography is rarely used.
Differential Diagnosis
Left atrial myxomas should be differentiated from mitral stenosis. Patients with mitral stenosis often have a loud opening snap, rarely have a fourth heart sound, and murmurs do not change with body position, without a to-and-fro sound. If suspected, echocardiography can be performed for differentiation. Left atrial spherical thrombi are also easily confused with left atrial myxomas. In echocardiography, most left atrial thrombi appear on the posterior wall of the left atrium, and their abnormal reflective light clusters lack the rapid movement characteristics of the cardiac cycle. Left atrial thrombi often occur with mitral stenosis, and thus abnormal reflective patterns of mitral valve movement can also be seen.
Right atrial myxomas should be differentiated from constrictive pericarditis, tricuspid stenosis, and pulmonary valve stenosis. The systolic-diastolic frictional to-and-fro murmur at the 3–4 intercostal spaces of the left sternal border, along with symptoms and murmurs related to body position changes, 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 diagnosis, early cardiac tumor resection should be performed to obtain better results.