What are the other Names for this Condition? (Also known as/Synonyms)

• Endocardial Sclerosis
• Fetal Endomyocardial Fibrosis
• Subendocardial Sclerosis

What is Endocardial Fibroelastosis? (Definition/Background Information)

• Endocardial Fibroelastosis (EFE) is a rare heart condition in which the muscular lining of the heart chambers thicken. The thickening occurs because of an increase in elastic fibers and supporting connective tissue
• In most cases, the condition affects young children, especially infants. The risk factors for Endocardial Fibroelastosis include aortic stenosis, cardiomyopathy, and ventricular septal defect, besides certain infections and immunologic conditions
• The cause of development of Endocardial Fibroelastosis is generally unknown. It may be associated with certain inherited genetic changes. EFE can lead to shortness of breath, feeding difficulties, and failure to thrive
• A treatment of Endocardial Fibroelastosis may involve the administration of medications and surgery, if needed. The prognosis may vary from one case to another, but is generally unfavorable

Who gets Endocardial Fibroelastosis? (Age and Sex Distribution)

• The exact incidence and prevalence of Endocardial Fibroelastosis (EFE) is unknown due to its relative rarity. It is noted that the number of reported cases of EFE is steadily declining over the last 20-30 years
• This heart abnormality is typically seen among the pediatric population, in children below the age of 2. Infrequently, it may be observed in adults
• Both males and females are equally affected
• There are no known racial or ethnic group predilection, and the condition is seen worldwide

What are the Risk Factors for Endocardial Fibroelastosis? (Predisposing Factors)

The following risk factors for Endocardial Fibroelastosis are identified:

• Individuals with the following conditions:
  • Anomalous origin of left coronary artery from the pulmonary artery
  • Aortic stenosis or atresia (including coarctation of the aorta)
  • Cardiomyopathy
  • Metabolic or carnitine deficiency disorder
  • Myocardial injury from any cause
  • Subendocardial ischemia
  • Ventricular septal defect
• Immunologic diseases
• Viral infections such as mumps and coxsackievirus B infection
• Congenital malformations
• Severe electric shock, including lightning strike (very uncommon though)

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Endocardial Fibroelastosis? (Etiology)

Endocardial Fibroelastosis (EFE) is termed primary or secondary. While primary is rare nowadays and noted in infants and young children, secondary arises from congenital heart conditions such as aortic stenosis and aortic atresia.

• It is reported that Endocardial Fibroelastosis may be caused due to certain genetic changes. Genes on X chromosome have been linked to the inherited form of the disorder (X-linked recessive). In some cases, it may be inherited as an autosomal recessive genetic trait
• It is also observed that the condition may develop with no apparent or identified cause (idiopathic). In such cases, it is suspected that the cause may probably be due to viral infections

Autosomal recessive inheritance: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

X-linked recessive: X-linked recessive conditions are traits or disorders that occur when two copies of an abnormal gene are inherited on a sex chromosome (X or Y chromosome). All X-linked recessive traits are fully evident in males because they have only one copy of the X chromosome. This means that there is no normal gene present to mask the effects of the mutant copy. All males who are affected will pass the mutated gene onto their female offspring, because they must inherit one copy of the X chromosome from each parent. This means that they will be unaffected carriers. Females are rarely affected by X-linked recessive disorders because they have two copies of the X chromosome. In the rare case that they inherit two mutated copies of the gene, they will inherit the condition.

What are the Signs and Symptoms of Endocardial Fibroelastosis?

The signs and symptoms of Endocardial Fibroelastosis (EFE) may be mild or severe and can vary from one individual to another, depending on the underlying cause. These may include:

• Feeding difficulty in children
• Excessive sweating
• Breathlessness and wheezing
• Failure to thrive
• Primary EFE in children may appear as heart failure, or occasionally as hydrops fetalis 

How is Endocardial Fibroelastosis Diagnosed?

The following tests and exams may be considered towards diagnosing:

• Diagnosis is by clinical evaluation - physical examination to look for the signs of respiratory distress (rales) and abnormal heart rhythms
• Radiographic studies (X-ray) may reveal heart enlargement, especially of the left ventricle 
• Damage to the heart may be assessed by taking an electrocardiogram (ECG) which may show subtle wave changes; this can be also used in monitoring the disease
• Biopsy of the endocardium of the heart: A tissue biopsy is performed and sent to a laboratory for a pathological examination, who examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Endocardial Fibroelastosis?

The possible complications of Endocardial Fibroelastosis include:

• Cardiac failure
• Recurrent chest infections
• Severe failure to thrive
• Cardiac cirrhosis
• Formation of cerebral, coronary, and pulmonary clots
• Collapse of left lung

How is Endocardial Fibroelastosis Treated?

Endocardial Fibroelastosis is treated the same as heart failure, and treatment with digoxin therapy is used and continued up to years after initial symptoms disappear.

• In most cases of heart failure, medications help to control symptoms and improve blood flow. A variety of medications are used, including:
  • Diuretics: It helps frequent in urination, thereby preventing fluid collection in the body
  • Angiotensin-converting enzyme (ACE) inhibitors - to help widen the blood vessels and improve blood flow; this helps decrease the blood pressure and stress on the heart muscles
  • Angiotensin II receptor blockers - these work in the same manner as ACE inhibitors
  • Digoxin - increases cardiac output by improving heart muscle contractions
  • Beta blockers - to help reduce blood pressure and slow heart rate
  • Usually, multiple medications must be taken together to improve symptoms

If the damage from acute heart failure is severe and likely to cause further, permanent health issues, surgery may be suggested. Thus, a coronary bypass surgery, heart valve repair, or insertion of a pacemaker or defibrillator may be undertaken.

How can Endocardial Fibroelastosis be Prevented?

Presently, there are no known preventive measures available for Endocardial Fibroelastosis. An early diagnosis and prompt treatment of the underlying causative conditions/infections may help in mitigating the risks.

What is the Prognosis of Endocardial Fibroelastosis? (Outcomes/Resolutions)

Idiopathic Endocardial Fibroelastosis (without any cause) has a relatively poor prognosis. The prognosis is worse if early onset of heart failure occurs.

• Heart failure can occur typically by age two, but sometimes children are known to survive until the age of 5
• Acute cardiac failure can occur after stopping treatment, even if the heart has returned back to a normal size

Additional and Relevant Useful Information for Endocardial Fibroelastosis:

The number of cases of Endocardial Fibroelastosis is on the decline. Some reports indicate that this may be due to a decrease in the number of cases of mumps.