The term endocardial elastosis was first introduced by Weinberg and Himmelfarb in 1943 and refers to a diffuse thickening of the endocardium from normal thin and transparent to porcelain white opaque due to massive infiltration of collagen and elastin fibers. Clinically, it often presents as heart failure, mostly in infants, but has been occasionally reported in children and adults. The disease may be present alone or secondary to or coexisting with a variety of congenital heart diseases, such as: ductus arteriosus, hypoplastic left heart syndrome, aortic stenosis or atresia, aortic constriction, and left coronary artery originating from the pulmonary artery.
1.Pathological mechanism
EFE is characterized by diffuse thickening of the endocardium and reduced cardiac function. It is currently believed that endocardial thickening is the result of myocardial damage or mitral valve insufficiency leading to long-term increased ventricular wall tension, and it progressively worsens with age. The endocardium may be diffusely thickened to 1-2 mm and is milky, reflective, and opaque. The heart is spherically enlarged, mainly involving the left ventricle and left atrium. The fibrosis may involve the papillary muscle and tendon cords, which have a high origin and short, thick tendon cords, and a curled mitral valve edge with poor docking. 50% of cases have mitral valve or aortic involvement, causing valve stenosis or incomplete closure. Microthrombi may be present on the endocardial surface. Ventricular wall thickness and coronary artery internal diameter are approximately normal.
The disease may be associated with viral infection. 1962 Fruhling et al. found a significant increase in the incidence of EFE after a coxsackievirus epidemic. autopsies showed different stages of simple myocarditis, myocarditis combined with EFE, and residual EFE after myocarditis was cured, and coxsackievirus could be cultured in the tissue. noren et al. injected mumps virus into chicken embryos, which initially presented with myocarditis and then developed typical EFE one year later. Towbin et al. processed EFE postmortem specimens from the years before mumps vaccination with modern genetic methods and the genome of mumps virus was found in the tissues of 80% of cases. It is therefore believed that transplacental transmission of mumps virus may have been the major causative agent of EFE in the past and that the incidence of EFE has decreased significantly with the introduction of mumps vaccination.
Non-infectious pathogenic factors also exist in EFE. The disease can be inherited autosomal or X chromosome recessive. the G4.5 gene variant is associated with EFE and Barth syndrome and can cause morphological changes in the embryonic heart at 18 weeks of gestation.
2. Epidemiology
The incidence of EFE in the United States was 1:5000 in 1964, and then decreased significantly for unknown reasons, currently believed to be related to the decrease in the prevalence of mumps. 1978 foreign statistics EFE accounts for about 1-2% of all congenital heart disease. This disease has been rare in developed countries, but is not uncommon in China. In China, the 9 provinces and cities myocarditis collaborative group statistics this disease accounted for about 0.3% of all hospitalized children.
The disease is mostly disseminated, with familial cases seen in 10% of patients. 80% of cases have an age of onset in the first 3-6 months of life, and the age of diagnosis is often 2-12 months after birth. There is no difference in gender.
3. Clinical manifestations
The disease often presents clinically as left heart insufficiency, and the main symptoms include shortness of breath, excessive sweating, feeding difficulties, and growth retardation. 20% of children have a history of recurrent or recent respiratory infections. The disease can also cause cardiogenic shock or sudden death.
Signs of the disease often include enlargement of the heart, normal or reduced first and second heart sounds, third heart sound or even gallop rhythm, systolic murmur of mitral valve incomplete closure, and enlarged liver and spleen.
4.Auxiliary tests
(1) Laboratory tests
In addition to routine blood tests, liver and kidney functions, electrolytes, cardiac enzymes and other routine tests, virus antibodies and autoimmune antibodies, such as anti-Ro and anti-La antibodies, can be examined.
(2) Electrocardiogram
Left ventricular hypertrophy is seen in more than 75% of children. Rightward deviation of the inner electrical axis and simple right ventricular hypertrophy are more common in the first few weeks of life. Pulmonary hypertension may be present in older children, and the ECG may show biventricular hypertrophy. 5% of patients may have low voltage early in the course of heart failure or at the end of the disease. 50% of children may have left atrial, right atrial or biventricular enlargement, and ST-segment depression, T-wave inversion or hypoplasia are also common ECG findings. Possible arrhythmias include pre-excitation syndrome, left bundle branch block, supraventricular or ventricular arrhythmias, and varying degrees of atrioventricular block.
(3) Chest radiograph
The main findings are cardiac enlargement and pulmonary venous stasis. The enlargement of the heart may appear after birth or may be normal after birth and increase in size only after a few weeks or months. 25% of children have left lower lobe atelectasis due to compression of the left main bronchus by the enlarged left atrium.
(4) Echocardiography
Echocardiography is the main diagnostic method for EFE. It reveals left atrial left ventricular enlargement, ventricular wall hypokinesis, reduced left ventricular ejection fraction and varying degrees of mitral regurgitation. Endocardial thickening and echogenic enhancement of the left ventricle are of great diagnostic value.
(5) Magnetic resonance imaging (MRI)
The value of MRI in the diagnosis of EFE has been emphasized in recent years. MRI can determine the presence of EFE by perfusion and delayed enhancement imaging of the myocardium. In perfusion imaging, EFE appears as a ring of low-intensity signal on the endocardial surface, while in delayed enhancement imaging of the myocardium, it appears as a high-intensity signal.
(6) Endomyocardial biopsy
Endomyocardial biopsy is feasible for cases with unclear diagnosis. The pathological changes are mainly in the endocardium, which shows infiltration of collagen fibers and elastic fibers proliferation. Fibrin deposition on the endocardial surface was also seen by electron microscopy. The myocardial layer is generally normal, and the myocardium with inflammatory changes can be called endocardial cardiomyopathy.
5. Diagnosis and differential diagnosis
Refer to the diagnostic criteria of the 9 Provinces and Cities Cardiomyopathy Collaborative Group.
(1) Early (often within 1 year of age, especially within 6 months) onset of heart failure with effective digitalis treatment, but with a long and often recurrent course.
(2) murmurs are generally mild or absent, and systolic murmurs of grade II or higher suggest mitral valve closure insufficiency.
(3) Chest radiograph shows pulmonary stasis and enlarged cardiac shadow, mainly in the left heart.
(4) Electrocardiogram shows left ventricular hypertrophy, ST-T changes, and arrhythmia in a few cases.
(5) Echocardiographic findings of endocardial changes and reduced cardiac function may provide the most important diagnostic basis.
(6) Exclude other cardiovascular disorders.
The disease needs to be differentiated from diseases such as left coronary artery originating from the pulmonary artery and glycogen accumulation disease. The presence of abnormal deep and wide Q waves with T-wave inversion in ECG I, avL, V4-V6 is highly suggestive of ALCAPA. Echocardiographic features include a ratio of the right coronary artery to the inner diameter of the aortic root exceeding 0.20, no vessels or normal blood flow in the left coronary position, collateral blood flow in the ventricular septum, enhanced echogenicity of the papillary muscle, and a red blood flow bundle converging into the pulmonary artery on the pulmonary valve.
6.Treatment
The treatment of EFE is mainly aimed at chronic cardiac insufficiency. Digoxin increases myocardial contractility, slows heart rate, and inhibits sympathetic nerves. Angiotensin-converting enzyme inhibitor (ACEI) can reduce afterload and improve left ventricular remodeling. Furosemide and spironolactone are commonly used diuretics in clinical practice. Early application and long-term maintenance of these drugs may improve the prognosis of children. β-blockers may improve the clinical prognosis of adults with heart failure, but their efficacy in children is still under observation. Treatment with gammaglobulin, glucocorticoids, or immunosuppressive agents may be added in more severe cases or when treatment is unsatisfactory. Anticoagulation should be administered in case of thromboembolic complications.
7.Prognosis
Early diagnosis and long-term maintenance therapy are essential for the prognosis of EFE. It is believed that 1/3 of patients can be completely cured and discontinued. Indications of poor prognosis include.
(1) manifestation of heart failure in the neonatal period.
(2) Recurrent episodes of heart failure despite aggressive treatment.