Overview

Cardiomyopathy is a disease that affects the heart muscle (myocardium). This condition makes it difficult for the heart to pump blood properly to the rest of the body. When the heart is unable to pump adequately, this can lead to a range of complications, including heart disease and eventually, heart failure. Cardiomyopathy is divided into three types: dilated, restrictive and hypertrophic cardiomyopathy.^1,2,3

Restrictive cardiomyopathy is a less common but serious form that affects the ventricles of the heart (lower chamber). In this form, the ventricular walls become stiff, reducing the heart’s ability to fill with blood. As a result, blood volume is reduced, leading to increased pressure in the heart and fluid buildup in the lungs. Over time, this dysfunction can result in heart failure and systemic fluid accumulation, affecting the lungs and other organs. In severe cases, surgical intervention may be required.^1,2,3,4

Restrictive cardiomyopathy

Restrictive cardiomyopathy (RCM) is a condition affecting the heart muscles, especially the ventricles. It can cause decreased blood volume and increase the ventricular pressure. Although the overall size of the heart is typically normal or only marginally enlarged, the condition leads to significant atrial dilation. This leads to fluid buildup in the body, including the lungs. This condition can cause an irregular rhythm of the heartbeat and can lead to heart failure. The clinical presentation of RCM is often subtle at first, with symptoms worsening gradually as the condition progresses. Surgical intervention may be necessary to manage complications.^4,5

Causes

Some of the underlying disease conditions include: 

Amyloidosis 

Amyloidosis is a rare disease that involves the abnormal deposition of the protein amyloid in the various organs, including the heart, and affects them. This can affect the heart, liver, kidney, spleen, and digestive and nervous systems. Cardiac amyloidosis is now recognised as the most frequent cause of RCM, particularly in older patients. It is mostly asymptomatic in the initial stage, making early diagnosis challenging. However, as the protein deposits increase, they cause the heart muscle to stiffen, impairing diastolic function.⁶ 

Sarcoidosis

Sarcoidosis is an inflammatory condition where the immune system overreacts and causes lumps or nodules in the organs, including the heart, called granuloma. When these granulomas form in cardiac tissue, they disrupt normal function and lead to restrictive physiology. Granulomas can cause mild to severe symptoms according to the location and size of its occurrence, and in some cases, they may not have any symptoms.^7,8

Haemochromatosis

Haemochromatosis is a genetic disorder in which the body absorbs too much iron from the food taken. This excess iron accumulates in organs like the heart, liver and pancreas, causing significant tissue damage, which leads to a life-threatening condition. When the heart is involved, iron deposits lead to the stiffening of the myocardial tissue and impaired cardiac function.⁹

Connective tissue disease

Connective tissues support and bind various structures in the body. Conditions such as systemic lupus erythematosus and rheumatoid arthritis can affect these tissues. Connective tissues are composed primarily of two proteins: collagen and elastin. When a patient is diagnosed with a connective tissue disease, it indicates inflammation or dysfunction of collagen and elastin, which may impair the normal function of multiple organs, including the heart.

Scleroderma

Scleroderma is an autoimmune disease that primarily affects the skin, causing hard and thickened areas. In some cases, it may also affect bones, muscles, blood vessels, and internal organs. Cardiac involvement in scleroderma can lead to stiffening of the myocardium, mimicking the features of RCM.

Eosinophilic endomyocardial disease

Also known as fibroblastic endocarditis, eosinophilic endomyocardial disease is a rare condition characterised by the proliferation of fibroblasts and inflammatory cells within the heart. This leads to myocardial damage and decreased compliance of the ventricular walls, contributing to restrictive cardiac physiology.¹⁰

Iatrogenic causes

Certain treatments for cancer, such as specific chemotherapy agents and radiation therapy, have been linked to RCM. While these therapies are critical in treating malignancies, their long-term cardiac effects continue to be an area of active research. 

Symptoms

Some of the common symptoms of RCM include: 

Chest pain 

Patients may experience sharp or dull chest pain, often described as a feeling of tightness. This discomfort can radiate to the arms, neck, or jaw. In some cases, the pain may be severe enough to mimic ischaemic heart disease and can present as a potentially life-threatening condition.

Oedema

Also known as swelling, oedema is caused by fluid buildup in the tissues due to elevated venous pressure. It most commonly affects the feet, ankles, and legs.

Nausea and fatigue

Nausea is an uncomfortable sensation in the stomach or throat that can be accompanied by the urge to vomit. Fatigue refers to extreme tiredness, often caused by the heart’s inability to pump blood effectively. This can make it difficult for individuals to carry out everyday activities.

Shortness of breath

Also known as dyspnoea, this symptom is particularly noticeable during physical exertion or when lying flat (orthopnoea). It is a hallmark of RCM, resulting from increased pressure in the pulmonary circulation due to the backflow of blood.

Heart palpitations

This refers to the sensation of a fast, irregular, or pounding heartbeat. Palpitations are often related to atrial enlargement and the electrical instability associated with RCM. They can increase after doing any activities like exercise or when a person feels anxiety, and in some cases, it may be due to certain medical conditions.

Heart size

In RCM, the heart size is normal or slightly enlarged. However, the stiffness of the heart muscle impairs proper blood flow, causing blood to back up into the circulatory system. This increases ventricular pressure and leads to atrial enlargement, irregular heart rhythms, and reduced pumping efficiency.

Diagnosis

Diagnosis of RCM involves a combination of clinical evaluation, imaging, and laboratory tests. The healthcare provider will examine the patient and ask about their medical and family history. Key diagnostic tools include:

Blood test

Complete blood tests can help identify abnormalities such as reduced iron levels or dysfunction in the thyroid, kidney, or liver. They may also detect inflammatory markers or abnormal proteins suggestive of amyloidosis.

Medical history and physical examination

A thorough medical history, including symptoms, previous conditions, and family background, is essential. Physical examination may reveal signs of fluid overload, such as peripheral oedema and elevated jugular venous pressure.

Chest x-ray

This imaging test uses sound waves to produce images of the heart. It can detect abnormal heart wall stiffness and assess blood flow through the heart and its valves.

Echocardiogram

This imaging test uses sound waves to produce images of the heart. It can detect abnormal heart wall stiffness and assess blood flow through the heart and its valves.

Electrocardiogram (ECG)

​​An ECG records the heart’s electrical activity and can identify arrhythmias and other irregular conditions associated with RCM.

Treadmill stress test (TMT)

During a treadmill stress test, the person is asked to walk on the treadmill, and the heart is monitored. This test shows how the heart reacts to physical activity.¹¹ 

Cardiac catheterisation

This procedure helps in identifying any blockage in the blood vessels and also helps in collecting tissue samples of the heart for biopsy. The catheter is a thin tube which is inserted through the groin to the blood vessels, which helps in measuring the pressure in the heart. Dye can be injected through the catheter into the blood vessels, which helps in identifying the blocked blood vessel. This is known as a coronary angiogram. 

Cardiac MRI 

This scan uses magnetic and radio waves to give a detailed images of the heart and its structures. 

Cardiac CT scan

In this procedure, multiple x-ray beams are used from different angles to acquire high-resolution three-dimensional images of the heart, blood vessels and surrounding structures. 

Management and treatment

RCM is treated according to the underlying disease condition and the severity of its occurrence.

Medication 

Doctors prescribe medication which helps in improving blood flow, stabilises the blood pressure, removes the extra fluid from the body, lowers the heart rate and prevents blood clots. Commonly prescribed medications include:

• Diuretics
• Beta-blockers
• ACE inhibitors or Angiotensin receptor blockers (ARBs)
• Anticoagulants

Surgery

Surgery is opted for severe conditions where certain heart monitoring devices are placed, which helps the heart to work properly and reduces the disease symptoms. Some of the procedures are: 

Ventricular assist device (VAD)

VAD is a circulatory support device which can be used for treating the person long-term or can be used as short-term. It is a device which helps in the proper flow of the blood from the lower ventricles to the other parts of the body. 

Cardiac resynchronization therapy device (CRT)

CRT is a dual-chamber pacemaker which coordinates the upper heart chambers (atria) and lower heart chambers (ventricles) and helps to restore the normal heartbeat rhythm.

Heart transplant 

Heart transplant is a treatment opted for the end stage of heart failure, where the treatments have failed, and the diseased heart is replaced with a donor's healthy heart through surgery. Although transplantation is a major procedure with significant risks, it can dramatically improve the quality of life and survival in selected patients.

Additional consideration

Alongside medical and surgical treatments, some other changes and continuous monitoring can help to reduce the risks of RCM. 

• Lifestyle modifications (e.g. low-sodium diet, moderate exercise)
• Regular monitoring
• Patient education on symptom management and medication adherence

FAQs

Can a person recover from restrictive cardiomyopathy?

Restrictive cardiomyopathy is treated according to its underlying cause. In cases with fewer symptoms, the healthcare provider prescribes medications, and in severe conditions, surgery and heart transplants are recommended for full recovery. 

What is the most common cause of restrictive cardiomyopathy?

Cardiac amyloidosis is the most common cause, where the increased accumulation of protein in the body affects the organs.

What are complications associated with restrictive cardiomyopathy?

Patients with RCM are at the risk of developing arrhythmias and thromboembolic events such as:

• Abnormal heartbeat
• Stroke
• Heart failure

Summary

Restrictive cardiomyopathy is a condition affecting the heart muscles, especially the ventricles. It can cause decreased blood volume and increase the ventricular pressure, and the atria becomes enlarged. This leads to fluid buildup in the body, including the lungs. This condition can cause an irregular rhythm of the heartbeat and can lead to heart failure. Restrictive cardiomyopathy is treated according to the underlying disease condition and the severity of its occurrence. Diagnosis relies on comprehensive clinical assessment supported by advanced imaging techniques such as echocardiography, cardiac MRI, and CT scans. 

Medicines can reduce the milder symptoms, and in more severe conditions, surgery or a healthy heart transplant is recommended for full recovery. Early recognition and intervention remain the cornerstones of effective management in this challenging condition.