Endocardial fibroelastosis is one of the more common types of primary cardiomyopathy in children. The disease cause remains unclear, but recent studies suggest it may be related to immune mechanisms. The main pathological changes involve the proliferation of elastic and collagen fibers in the endocardium or (and) subendocardial tissues, thereby restricting both myocardial contraction and relaxation functions. The condition primarily affects the left ventricle and left atrium and is most frequently observed in infants under one year of age, though it may occasionally occur in young children or even school-aged children. Heart failure is often triggered by respiratory infections.

bubble_chart Type

Clinically, it can be classified into three types based on the severity and urgency of onset:

1. Fulminant type: The onset is acute, with sudden signs and symptoms of acute congestive heart failure. A few cases may present as acute cardiogenic shock, and the critical condition can lead to sudden death. This type mostly occurs in infants under 6 months of age.
2. Acute type: The onset is relatively rapid, but the progression of congestive heart failure is not as abrupt as in the fulminant type. Some cases may die from acute heart failure, but most can achieve remission with aggressive treatment and full recovery with long-term standardized therapy.
3. Chronic type: The onset is relatively slow, mostly occurring in infants and young children, with a few cases seen in preschool or school-age children. Most cases can achieve full recovery with standardized treatment.

bubble_chart Diagnosis

Currently, the diagnosis in China is mostly based on the criteria established by the Nine-Province Myocarditis Collaborative Group, as follows:

1. Early onset of congestive heart failure (often within the first year of life, especially within 6 months), frequently triggered by respiratory infections. Although Rehmannia-based medications remain somewhat effective, heart failure is often stubborn and prone to recurrent exacerbations. A very small number of cases may not present with heart failure.
2. Murmurs are mild or absent, with a few cases exhibiting a grade 2 systolic murmur suggestive of mitral regurgitation.
3. Chest X-ray reveals cardiac enlargement, predominantly in the left heart, often accompanied by pulmonary venous congestion, with weakened cardiac pulsations visible under fluoroscopy.
4. Electrocardiogram shows left ventricular hypertrophy, typically accompanied by ischemic T-wave inversion in the left precordial leads in addition to increased voltage. In rare cases, left ventricular hypertrophy may not be evident. Arrhythmias are uncommon.
5. Echocardiography aids in the diagnosis, revealing significant enlargement of the left ventricle and left atrium, weakened left ventricular wall motion, and enhanced brightness of the endocardium. Endocardial myocardial biopsy may be performed when feasible.

bubble_chart Treatment Measures

In recent years, the early application of digitalis Rehmannia and the additional use of adrenal corticosteroids targeting the immune mechanism of disease, along with long-term application, have achieved good results. Not only has the condition significantly improved, but many cases have also achieved complete recovery, with a marked decrease in mortality.

1. Digitalis Rehmannia preparation: Digoxin is generally used, administered orally or intravenously depending on the condition. The digitalization dose is 40–60 μg/kg, followed by 1/4 to 1/5 of the digitalizing dose as a maintenance dose, administered orally in two divided doses daily. The dose is adjusted with age, and the general treatment course lasts 3–4 years. Premature discontinuation may easily lead to recurrence of heart failure and relapse of the condition. The criteria for discontinuation include the disappearance of symptoms for over one year and the normalization of X-ray and electrocardiogram examinations. In cases of acute heart failure, vasodilators and diuretics may be combined as needed.
2. Adrenal corticosteroids: Prednisone is generally used at a daily dose of 1.5 mg/kg for 8–12 weeks, followed by gradual dose reduction. The medication duration is 1–1.5 years, until electrocardiogram and X-ray examinations approach normal. In recent years, for severe and acute cases, immunosuppressants such as cyclophosphamide have been added concurrently, with certain therapeutic effects.