Overview  

What is endomyocardial fibrosis?  

Endomyocardial Fibrosis (EMF) is a rare form of cardiomyopathy, a heart disease.¹ A general term for a collection of heart disorders which cause physical changes specifically to the heart's muscles and inner structures.² It is presented through an accumulation of fibrous tissue on the heart’s inner lining (endocardium), causing the normal movements of the heart to become restricted and unable to function effectively, leading to limited blood flow.¹ Depending on the severity, over time, this can progressively lead to complications such as heart failure.¹

Who is most at risk?  

Generally, EMF development is rare. Like other types of cardiomyopathies, it may be inherited, result from various risk factors, or develop due to underlying health conditions. In some cases, however, the exact cause may be unknown.¹ EMF is most commonly found in countries of low income, particularly in regions with lower socioeconomic status.² For example, a study in rural Mozambique reported that EMF accounted for 20% of heart failure cases.3 There is no specific age range or gender universally at risk; however, diagnoses are more frequently reported in people assigned female at birth¹ and children.³

Endomyocardial fibrosis and heart failure  

What causes EMF?  

EMF is primarily recognised to be caused by an immune response triggered by exposure to pathogenic (an organism that causes disease)⁶ exposure.⁷ A link between EMF and the individuals who get the disease has been observed in patients with backgrounds from low-income countries due to poor nutrition and exposure to harmful pathogens.⁷   

How does EMF develop in the body?   

After an infection, the body initiates an immune response. In EMF, the infection is triggered by damage to the heart's endocardium.¹ The body’s immune response increases blood flow to the affected area, leading to inflammation, which can cause harm to the endocardial tissue.¹ As part of the healing process, fibrogenesis is activated (the formation of scar tissue using extracellular matrix components). Excessive extracellular molecules are deposited as a protective mechanism, causing the heart’s tissue to thicken from scar tissue formation,⁴ progressively resulting in endomyocardial fibrosis.  

How EMF causes heart failure  

Ongoing or excessive fibrogenesis in Endomyocardial Fibrosis causes the heart to become restrictive in its movements, impairing the heart's ability to function normally. As a result, during the heart's diastolic phase, the heart struggles to fill adequately with blood and the blood is subsequently not pumped effectively.¹  Because of this, blood circulation is reduced, leading to an inadequate oxygen supply to the body's tissues, producing heart failure symptoms.¹  

Significance of heart failure in EMF patients   

While not all patients with EMF will develop heart failure, it is a common outcome due to disease progression. This risk varies depending on the severity of the condition and the treatment received.¹ The presence of fibrous tissue in EMF patients also increases the likelihood of serious complications such as thrombus formation, stroke, and arrhythmias,⁵ highlighting the severity of the disease.¹

Clinical presentation

Signs and symptoms   

As EMF restricts the heart's normal movements, its normal function becomes impaired, leading to symptoms such as:⁷  

• Irregular and weakened heartbeat   
• Breathing difficulties  
• Physical strain   
• Poor circulation   

Physical symptomatic changes of the body include:⁷  

• Organ enlargement (this includes the heart, spleen and liver)  
• facial inflammation  
• Leg inflammation   
• Fluid retention   

Common complications   

Due to the significant changes EMF has on the heart's structure and function, other complications may result.   

Heart failure  

Within the heart's cardiovascular system, the heart goes through a series of phases, one of which is the diastolic and systolic phase. In diastole, the heart muscles relax, allowing the heart to fill with blood, whereas in systole, the heart muscles contract, pumping out blood to the rest of the body.⁸ Due to the restrictive nature of this disease, during diastole the heart isn't able to fill effectively, manifesting as heart failure, which if untreated, can further complicate into cardiac shock, organ failure or needing urgent professional intervention.¹

Arrhythmias  

In EMF, damage to the heart's electrical system can cause an irregular heartbeat.¹ This can worsen the condition, its outcomes, and increase the risk of blood clots and heart failure.¹

Thromboembolism

Fibrotic tissue build-up on the heart's endocardium increases the risk of blood clot formation within the chambers of the heart. This can worsen the condition and increase the risk of stroke.¹ 

Faulty heart valves

The presence of fibrosis in the heart can also spread to the heart's valves. These valves, which would usually prevent the backflow of blood, would now be restricted and not allow blood to flow in its correct path, impacting blood flow and worsening heart failure symptoms.¹

Pulmonary hypertension

EMF affects not only the heart but also other organs in the body. Over time, heart failure can lead to increased pressure in the lungs, resulting in respiratory symptoms such as shortness of breath, which can further worsen the signs of heart failure.¹  

Endocarditis   

The damage caused by EMF makes the heart more vulnerable to infections carried through the bloodstream.¹  

Pericardial effusion   

The effects of inflammation from EMF can cause pericardial effusion.¹ Where fluid builds up around the heart, contributing to heart failure due to the increased pressure.⁹

Cardiac death

In rarer cases, an infected individual may develop multiple complications associated with endomyocardial fibrosis, ultimately resulting in cardiac death.¹

Diagnostic evaluation and diagnosis

Diagnosis is case-specific, as there is a range of diagnostic methods.⁷ Which are dependent on the individual patient. Primarily, echocardiography is the most common tool to spot and review the presence of EMF.⁷ Other useful methods include heart muscle biopsy, blood tests to check organ function and Magnetic resonance imaging (MRI)/ Computerised Tomography (CT) scans.¹

Management strategies

There is a range of management strategies that focus on relieving symptoms and treating irreversible damage as much as possible.

Medical management  

Medical management uses medications to manage symptoms such as arrhythmias. These include diuretics, ACE inhibitors, Beta-blockers, and Aldosterone antagonists.¹ Another form of medical management is to try and target the occurrence of thrombosis using anticoagulants.¹

Nutritional and supportive care

Nutritional and supportive care involves management of inflammatory fluid buildup around the heart using diuretics.¹¹ Treating other underlying conditions, which may be making EMF worse, is also important, as it will help to promote treatment.¹¹

Surgical and interventional approaches  

Surgical approaches are usually used as a secondary treatment approach when other medical methods may not have been successful or if the disease is at a severe stage.⁷ Methods used are endocardectomy¹ and prosthesis valve replacement¹ to help restore valve function and reduce symptoms.   

Outcomes  

Outcomes for patients with Endomyocardial fibrosis are generally poor due to heart failure progression being high and hard to recover from.¹  

Studies have shown a 75% death rate in patients experiencing end-stage heart failure in a course of 2 years following management.¹ This usually occurs due to the severity of heart failure and subsequent symptoms affecting the normal functioning of the heart.¹¹

Surgical management vs medical 

Out of the management methods, surgery completed correctly has been seen to be most effective in helping to correct the physical damage caused by EMF³ and reducing heart rate symptoms. Medical management, however, being the primary focus of care may not be suitable for patients with severe heart failure symptoms; therefore, it is not effective for all, especially severe stage patients.³

Factors influencing treatment outcomes and disease recovery   

As EMF is most found in countries of low income,¹ availability and access to care, medication, and treatment can be a barrier and cause complications in receiving treatment. If left untreated, EMF will progressively get worse, limiting management strategies to help recover from heart failure damage. Additional people from low socioeconomic backgrounds may have more exposure to disease and be more susceptible to nutritional deficiencies, making them at risk of recurrent infection.¹

Summary

Endomyocardial Fibrosis is a rare heart condition where scar tissue builds up, stiffens the heart, making it restrictive to its function. This presents a range of symptoms such as tiredness, swelling, and trouble breathing. It’s most common in low-income regions, often linked to infections and a lack of proper nutrition. Treatments like medicines or surgery can ease symptoms and significantly improve the disease’s damage. However, the illness can be very serious if it progresses, making it difficult to treat.   

Keywords  

Endomyocardial fibrosis, cardiomyopathy, endocardium, cardiomyopathies, pathogenic, fibrogenesis, diastole, systole, inflammation, arrhythmias.